Cast-in-Place Concrete
Corpus sync: neutrality remakes, note hygiene, datasheet relocation, transformer-split cross-refs
Showing changes from Rev 6
to Rev 7
in Cast-in-Place Concrete.
−---
−title: Cast-in-Place Concrete
−category: Structural / Concrete
−toc_depth: 3
−description: >
− When to use: Cast-in-place (CIP) concrete for structural elements including foundations, footings, grade beams, slabs-on-grade, elevated slabs, walls, columns, beams, and other monolithic structural concrete placed in its final location. Covers concrete materials, mix design, formwork, reinforcement coordination, placement, consolidation, joints, finishing, curing, tolerances, field testing, and repair. Applicable to commercial, institutional, and industrial buildings and structures.
− Not intended for: Precast or prestressed concrete manufactured off-site, architectural or exposed decorative concrete requiring specialized finishes beyond basic formed or troweled surfaces, shotcrete, cellular lightweight concrete, mass concrete for dams, concrete paving or overlays, or concrete masonry units. Reinforcing steel detailing and fabrication are covered in [[sync/concrete-reinforcement]]. Below-grade waterproofing of concrete structures is covered in [[sync/below-grade-waterproofing]]. Thermal insulation of concrete assemblies is covered in [[sync/building-thermal-insulation]].
−---
−
−# Scope {toc}
−
−## This specification covers the materials, mix design, formwork, placement, consolidation, curing, and testing of cast-in-place structural concrete for buildings and structures. {note}
−
−## All concrete work shall conform to the requirements of ACI 301-20, Specifications for Concrete Construction, and where structural performance is specified by design, to ACI CODE-318-25, Building Code for Structural Concrete.
−
−## The requirements of this standard govern construction-level execution; structural design requirements shown on the contract drawings and in the structural specifications take precedence over default values where a more stringent requirement is expressed.
−
−## Cast-in-place concrete is not a single uniform material but a family of performance-engineered mixtures, each tailored to its structural function, exposure conditions, and service environment, and the consequences of defective concrete are severe because it is hidden within formwork until stripping and often structurally irreplaceable without demolition. {note}
−
−## Requirements for submittals, mix qualification, placement sequencing, consolidation, curing, and field testing are not administrative formalities; they are the controls that prevent defective work from being permanently incorporated in the structure. {note}
−
−## The Contractor shall coordinate reinforcing steel procurement, fabrication, and placement with [[sync/concrete-reinforcement]].
−
−## The Contractor shall coordinate below-grade moisture management with [[sync/below-grade-waterproofing]].
−
−## The Contractor shall coordinate thermal performance of concrete wall and roof assemblies with [[sync/building-thermal-insulation]].
−
−## This standard does not govern precast or prestressed concrete elements fabricated off-site, shotcrete, or concrete masonry.
−
−# Referenced Standards {toc}
−
−## All materials, production, placement, testing, and quality control shall comply with the latest adopted edition of the following standards.
−
−| Standard | Title |
−|----------|-------|
−| ACI 301-20 | Specifications for Concrete Construction |
−| ACI CODE-318-25 | Building Code for Structural Concrete — Code Requirements and Commentary |
−| ACI 117-10 (Reapproved 2015) | Specification for Tolerances for Concrete Construction and Materials |
−| ACI 305R-20 | Guide to Hot Weather Concreting |
−| ACI 306R-16 | Guide to Cold Weather Concreting |
−| ACI 308R-16 | Guide to External Curing of Concrete |
−| ACI 347R-14 | Guide to Formwork for Concrete |
−| ASTM C33/C33M | Standard Specification for Concrete Aggregates |
−| ASTM C39/C39M | Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens |
−| ASTM C94/C94M | Standard Specification for Ready-Mixed Concrete |
−| ASTM C138/C138M | Standard Test Method for Density (Unit Weight), Yield, and Air Content (Gravimetric) of Concrete |
−| ASTM C143/C143M | Standard Test Method for Slump of Hydraulic-Cement Concrete |
−| ASTM C150/C150M | Standard Specification for Portland Cement |
−| ASTM C172/C172M | Standard Practice for Sampling Freshly Mixed Concrete |
−| ASTM C173/C173M | Standard Test Method for Air Content of Freshly Mixed Concrete by the Volumetric Method |
−| ASTM C231/C231M | Standard Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method |
−| ASTM C260/C260M | Standard Specification for Air-Entraining Admixtures for Concrete |
−| ASTM C494/C494M | Standard Specification for Chemical Admixtures for Concrete |
−| ASTM C618 | Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete |
−| ASTM C989/C989M | Standard Specification for Slag Cement for Use in Concrete and Mortars |
−| ASTM C1064/C1064M | Standard Test Method for Temperature of Freshly Mixed Hydraulic-Cement Concrete |
−| ASTM C1077 | Standard Practice for Agencies Testing Concrete and Concrete Aggregates for Use in Construction |
−| ASTM C1157/C1157M | Standard Performance Specification for Hydraulic Cement |
−| ASTM C1231/C1231M | Standard Practice for Use of Unbonded Caps in Determination of Compressive Strength of Hardened Cylindrical Concrete Specimens |
−| ASTM C1240 | Standard Specification for Silica Fume Used in Cementitious Mixtures |
−
−## Where the contract documents, building code, or a referenced standard conflict, the more stringent requirement governs unless the Engineer of Record directs otherwise in writing.
−
−# Submittals {toc}
−
−## Action Submittals {toc}
−
−### Contractor shall submit the following for the Engineer's review prior to procurement and placement:
−
−- Concrete mix designs for each concrete class, prepared in accordance with ACI 301-20, showing all cementitious materials, aggregates, admixtures, water content, and target water-to-cementitious materials ratio (w/cm); trial batch or field-record documentation establishing the required average compressive strength (f'cr) in accordance with ACI 301-20 Section 4.2; and the standard deviation of the proposed mix used to calculate f'cr
−- Product data for all cementitious materials, aggregates, admixtures, and curing compounds, including certifications of conformance to the applicable ASTM standards listed above
−- A concrete placement plan for elements that require a pour sequence, including elevated slabs, walls, and any element exceeding 50 cubic yards in a single placement; the plan shall identify pour sequence, joint locations, anticipated concrete temperature at delivery, anticipated ambient conditions, and planned method of consolidation
−- Formwork design or shop drawings prepared, signed, and sealed by a registered professional engineer licensed in the state of the project, covering all shoring and reshoring, centering, and any formwork element for which design is required by ACI 347R-14 or where loads exceed standard load tables
−- Proposed curing plan, including materials, method, duration, and temperature monitoring procedure for each exposure condition anticipated on the project
−- For pre-purchased reinforcing steel or embeds: shop drawings conforming to [[sync/concrete-reinforcement]]
−
−```datasheet
−label: Action Submittals Required
−type: checkbox
−options:
− - "Concrete mix designs for all classes"
− - "Cementitious material certifications"
− - "Aggregate certifications and gradations"
− - "Admixture product data"
− - "Concrete placement plan"
− - "Formwork design by licensed engineer"
− - "Curing plan"
− - "Reinforcing steel shop drawings"
−default: "Concrete mix designs for all classes"
−```
−
−### No concrete placement shall proceed on any element until the corresponding submittals have been reviewed and accepted.
−
−### Submittals shall be complete at the time of submittal — piecemeal submissions shall be rejected.
−
−## Informational Submittals {toc}
−
−### Prior to placement, Contractor shall submit the following:
−
−- The name and ASTM C1077-compliant qualifications of the proposed concrete testing agency
−- The concrete producer's batch plant qualification records, including plant certification status
−- A list of all personnel who will perform field concrete testing, with current ACI Concrete Field Testing Technician Grade I or equivalent certifications
−
−```datasheet
−label: Informational Submittals Required
−type: checkbox
−options:
− - "Concrete testing agency name and ASTM C1077 qualifications"
− - "Concrete producer batch plant qualification records"
− - "Field testing personnel certifications (ACI Grade I or equivalent)"
−default: "Concrete testing agency name and ASTM C1077 qualifications"
−```
−
−## Closeout Submittals {toc}
−
−### Contractor shall provide the following at substantial completion before concrete work is accepted:
−
−- All field test reports including compressive strength results, fresh concrete test data, temperature logs, and corrective action records; reports shall be organized by concrete class and pour date
−- As-built joint layout diagram showing all construction joints, expansion joints, contraction joints, and isolation joints as actually placed
−- Concrete repair documentation for any defects identified during construction and the repair method and materials used
−
−```datasheet
−label: Closeout Submittals Required
−type: checkbox
−options:
− - "Field test reports (strength, fresh concrete, temperature, corrective action)"
− - "As-built joint layout diagram"
− - "Concrete repair documentation"
−default: [Field test reports (strength, fresh concrete, temperature, corrective action), As-built joint layout diagram, Concrete repair documentation]
−```
−
−# Quality Assurance {toc}
−
−## Concrete Producer Qualification {toc}
−
−### All concrete shall be furnished by a ready-mix producer qualified in accordance with ASTM C94/C94M.
−
−### The producer shall operate a batch plant that has been inspected and meets the requirements of a recognized concrete plant quality program such as those administered by the National Ready Mixed Concrete Association (NRMCA) or an equivalent state or regional program, or shall demonstrate equivalent quality controls.
−
−### Contractor shall furnish the Engineer with evidence of producer qualification before the first delivery.
−
−## Testing Agency Qualifications {toc}
−
−### The Owner's independent testing agency shall meet the requirements of ASTM C1077 and shall be under the technical direction of a registered professional engineer.
−
−### Field sampling and testing technicians shall hold current certification in accordance with ASTM C1077, specifically covering ASTM C172, C31, C39, C138, C143, C173 or C231, and C1064.
−
−### Testing agency reports shall be submitted to the Engineer within 24 hours of each test.
−
−### The Contractor shall provide the testing agency with advance notice of each pour, safe access to the work, and cooperation during testing.
−
−### The testing agency is engaged by and reports to the Owner (or Owner's representative), not the Contractor, and presence of the testing agency does not relieve the Contractor of responsibility for meeting specification requirements; all acceptance decisions remain the Engineer's. {note}
−
−## Pre-Installation Conference {toc}
−
−### A pre-concrete conference shall be held before the first structural concrete placement, attended by the Contractor's superintendent, the concrete producer's representative, the testing agency's project manager, and the Engineer.
−
−### The agenda shall cover mix designs and approval status, placement sequence and joint locations, hot or cold weather contingency plans, consolidation equipment and methods, curing materials and duration, and the testing plan.
−
−## Mix Design Approval {toc}
−
−```datasheet
−label: Mix Design Qualification Basis
−type: radio
−options:
− - "Field test record — statistical record from production history (preferred)"
− - "Trial mixtures — at least three batches bracketing required strength"
− - "Combination of field record and trial batches"
−default: "Field test record — statistical record from production history (preferred)"
−```
−
−### No concrete mixture shall be used in the work until approved by the Engineer.
−
−### Where field test records are used, they shall include at least 30 test results from the proposed mix within the past 12 months, or the Engineer shall require an increase in f'cr per ACI 301-20 Table 4.2.1.
−
−### Mix design approval does not transfer liability for structural performance from the Contractor to the Engineer; the Contractor remains responsible for proportioning, batching, delivery, and placement in conformance with the approved design. {note}
−
−### Field test records are preferred because they reflect actual production variability; trial batches represent only laboratory conditions and typically overstate the quality of production concrete. {note}
−
−# Environmental and Service Conditions {toc}
−
−## ACI CODE-318-25 Chapter 19 establishes exposure categories that govern minimum w/cm and minimum specified compressive strength. {note}
−
−## The durability of concrete is primarily determined by the relationship between its mix design and the exposures it will encounter in service, and specifying strength alone without addressing exposure categories frequently results in concrete that meets structural strength requirements but degrades prematurely. {note}
−
−## Exposure Categories {toc}
−
−```datasheet
−label: Freeze-Thaw Exposure (ACI 318 Category F)
−type: radio
−options:
− - "F0 — Concrete not exposed to freezing and thawing in a moist condition or to deicing chemicals"
− - "F1 — Concrete exposed to freezing and thawing in a moist condition but not to deicing chemicals"
− - "F2 — Concrete exposed to freezing and thawing in a moist condition and to deicing chemicals"
−default: "F0 — Concrete not exposed to freezing and thawing in a moist condition or to deicing chemicals"
−```
−
−```datasheet
−label: Sulfate Exposure (ACI 318 Category S)
−type: radio
−options:
− - "S0 — Concrete not exposed to sulfates in soil or water"
− - "S1 — Concrete exposed to moderate sulfate concentrations in soil or water"
− - "S2 — Concrete exposed to severe sulfate concentrations"
− - "S3 — Concrete exposed to very severe sulfate concentrations"
−default: "S0 — Concrete not exposed to sulfates in soil or water"
−```
−
−```datasheet
−label: Contact with Water (ACI 318 Category W)
−type: radio
−options:
− - "W0 — Concrete dry in service"
− - "W1 — Concrete in contact with water where low permeability is not required"
− - "W2 — Concrete in contact with water where low permeability is required"
−default: "W0 — Concrete dry in service"
−```
−
−```datasheet
−label: Corrosion Protection of Reinforcement (ACI 318 Category C)
−type: radio
−options:
− - "C0 — Concrete dry or protected from moisture in service"
− - "C1 — Concrete exposed to moisture but not to external chlorides"
− - "C2 — Concrete exposed to moisture and an external source of chlorides"
−default: "C0 — Concrete dry or protected from moisture in service"
−```
−
−### The required maximum w/cm and minimum specified compressive strength shall be determined from ACI CODE-318-25 Tables 19.3.2 and 19.3.3 based on the above categories.
−
−### Where a structure contains elements with different exposures, each concrete class shall be selected to satisfy the most severe exposure applicable to that element.
−
−# Concrete Materials {toc}
−
−## Cementitious Materials {toc}
−
−### Portland Cement {toc}
−
−```datasheet
−label: Portland Cement Type
−type: radio
−options:
− - "Type I/II — General purpose"
− - "Type III — High early strength (requires Engineer approval)"
− - "Type V — Sulfate resistant (S2 or S3 exposure)"
−default: "Type I/II — General purpose"
−```
−
−#### Portland cement shall conform to ASTM C150/C150M.
−
−#### Type III cement (high early strength) shall be used only where accelerated strength gain is specifically required and approved.
−
−#### Type V cement is required for concrete in contact with soil or water containing severe or very severe sulfate concentrations (S2 or S3 exposure categories).
−
−#### Type V shall not be substituted with ordinary portland cement in S2 or S3 conditions, even with slag or fly ash supplementation, unless the combination has been demonstrated equivalent by testing per ACI 201.2R.
−
−#### Type I/II cement, which meets both Type I and Type II requirements, is the default and is appropriate for the majority of structural applications; Type III increases the risk of thermal cracking and rapid setting that complicates finishing in flatwork. {note}
−
−### Supplementary Cementitious Materials {toc}
−
−```datasheet
−label: Supplementary Cementitious Material (SCM) Used
−type: checkbox
−options:
− - "None — portland cement only"
− - "Fly Ash (ASTM C618 Class F)"
− - "Fly Ash (ASTM C618 Class C)"
− - "Slag Cement (ASTM C989)"
− - "Silica Fume (ASTM C1240)"
−default: "None — portland cement only"
−```
−
−```datasheet
−label: Fly Ash Replacement Rate (% by mass of cementitious materials)
−type: range
−unit: "%"
−options:
− min: 15
− max: 40
− step: 5
−default: 20
−```
−
−```datasheet
−label: Slag Cement Replacement Rate (% by mass of cementitious materials)
−type: range
−unit: "%"
−options:
− min: 20
− max: 50
− step: 5
−default: 30
−```
−
−#### Fly ash, ground-granulated blast-furnace (GGBF) slag cement, and silica fume may be used as partial replacements for portland cement where the mix design demonstrates compliance with all strength, durability, and workability requirements.
−
−#### Fly ash shall conform to ASTM C618, Class C or Class F.
−
−#### Slag cement shall conform to ASTM C989/C989M.
−
−#### Silica fume shall conform to ASTM C1240.
−
−#### SCMs generally reduce permeability and improve long-term durability, particularly for sulfate and chloride resistance, but fly ash and slag slow early strength gain, which must be accounted for when establishing stripping and loading schedules; silica fume substantially reduces permeability and is particularly effective in C2 exposure but requires careful water control and immediate curing due to its high surface area. {note}
−
−## Aggregates {toc}
−
−### Coarse Aggregate {toc}
−
−```datasheet
−label: Coarse Aggregate Nominal Maximum Size
−type: select
−unit: in
−options:
− - "3/8 in — columns with congested reinforcing, thin walls"
− - "1/2 in — typical columns and walls"
− - "3/4 in — general structural elements, most slabs"
− - "1 in — mass footings, large walls, and mat foundations"
− - "1-1/2 in — very large elements per Engineer approval"
−default: "3/4 in — general structural elements, most slabs"
−```
−
−#### Coarse aggregate shall conform to ASTM C33/C33M.
−
−#### The nominal maximum aggregate size shall comply with ACI CODE-318-25 Section 26.4.2.1, which requires that aggregate size shall not exceed three-quarters of the minimum clear spacing between reinforcing bars, one-third the depth of slabs, or one-fifth the narrowest dimension of a member — the least of these governs.
−
−#### Larger aggregate sizes shall only be used where member geometry and reinforcing congestion permit.
−
−#### The 3/4 in. maximum size is appropriate for the majority of structural concrete placements in buildings; larger sizes reduce water demand and improve economy in mass elements, and smaller sizes may be required in thin sections or elements with closely-spaced reinforcement. {note}
−
−### Fine Aggregate {toc}
−
−#### Fine aggregate shall conform to ASTM C33/C33M.
−
−#### The fineness modulus shall be between 2.3 and 3.1.
−
−#### Fine aggregate with organic impurities, deleterious materials, or clay content in excess of ASTM C33 limits shall be rejected.
−
−### Aggregate Reactivity {toc}
−
−```datasheet
−label: Aggregate Alkali-Silica Reactivity (ASR) Risk
−type: radio
−options:
− - "Low risk — aggregate source has acceptable service history or low expansion per ASTM C1260/C1293"
− - "Moderate risk — SCM mitigation included in mix design"
− - "Not yet evaluated — testing required prior to mix design approval"
−default: "Low risk — aggregate source has acceptable service history or low expansion per ASTM C1260/C1293"
−```
−
−#### Where aggregate sources are suspected of alkali-silica reactivity (ASR) or alkali-carbonate reactivity (ACR), aggregates shall be evaluated in accordance with ASTM C1260 or ASTM C1293 before use.
−
−#### Aggregate that tests expansive in accordance with ASTM C1260 or ASTM C1293 shall not be used unless the mix design includes measures demonstrated to mitigate expansion, such as adequate SCM content or use of low-alkali cement.
−
−## Water {toc}
−
−### Mixing water shall be potable water or water conforming to ASTM C1602/C1602M.
−
−### Non-potable water may be used only where tested and approved in accordance with ASTM C1602.
−
−### Seawater shall not be used as mixing water in any concrete containing reinforcing steel or other embedded metals.
−
−## Chemical Admixtures {toc}
−
−```datasheet
−label: Chemical Admixtures Used
−type: checkbox
−options:
− - "Type A — Water reducing"
− - "Type B — Retarding"
− - "Type C — Accelerating"
− - "Type D — Water reducing and retarding"
− - "Type E — Water reducing and accelerating"
− - "Type F — High range water reducing (superplasticizer)"
− - "Type G — High range water reducing and retarding"
− - "None"
−default: "None"
−```
−
−### Chemical admixtures shall conform to ASTM C494/C494M.
−
−### Only admixtures that are tested and shown to be compatible with the cementitious materials, other admixtures, and aggregate shall be used.
−
−### Admixture dosages shall be within the range tested in the mix design; field adjustments beyond that range shall require re-evaluation by the Engineer.
−
−### Water-reducing admixtures (Type A or F) are strongly encouraged in all structural concrete because they allow the target w/cm and strength to be achieved at reduced water content, which improves long-term durability and reduces shrinkage. {note}
−
−### Retarding admixtures (Type B or D) shall be required for placements where concrete temperature is anticipated to exceed 80°F at time of delivery or where extended haul distances risk initial set before placement is complete.
−
−### Accelerating admixtures (Type C or E) shall be evaluated for cold weather use when ambient temperatures are below 50°F, in coordination with the cold weather protection plan.
−
−### Calcium chloride shall not be used as an accelerating admixture in concrete containing reinforcing steel, prestressed elements, aluminum embeds, or galvanized steel.
−
−### Non-chloride accelerators conforming to ASTM C494 Type C shall be used instead of calcium chloride where an accelerator is required.
−
−## Air-Entraining Admixtures {toc}
−
−```datasheet
−label: Air Entrainment Required
−type: radio
−options:
− - "Not required — no freeze-thaw or deicing chemical exposure (F0)"
− - "Required — freeze-thaw exposure without deicing chemicals (F1)"
− - "Required — freeze-thaw and deicing chemical exposure (F2)"
−default: "Not required — no freeze-thaw or deicing chemical exposure (F0)"
−```
−
−```datasheet
−label: Total Air Content Target (ACI 318 Table 19.3.3.1)
−type: select
−unit: "%"
−options:
− - "Not applicable — no air entrainment required"
− - "4.5 ± 1.5% — 1-in. max aggregate, moderate exposure"
− - "6.0 ± 1.5% — 3/4-in. max aggregate, moderate exposure"
− - "7.5 ± 1.5% — 3/8-in. max aggregate, moderate exposure"
− - "4.5 ± 1.5% — 1-in. max aggregate, severe exposure"
− - "6.0 ± 1.5% — 3/4-in. max aggregate, severe exposure"
− - "7.5 ± 1.5% — 3/8-in. max aggregate, severe exposure"
−default: "Not applicable — no air entrainment required"
−```
−
−### Air-entraining admixtures shall conform to ASTM C260/C260M.
−
−### Air entrainment is required for all concrete exposed to freezing and thawing (F1 or F2 exposure) and for all concrete exposed to deicing chemicals.
−
−### The mix design shall be established to achieve the required f'c at the specified air content; the strength reduction caused by entrained air shall be accounted for in the mix design, not compensated for by adding water.
−
−### Air entrainment improves durability by creating a system of closely spaced microscopic air voids that relieve the pressure generated when pore water freezes and expands; without this relief, freeze-thaw cycling progressively destroys the concrete surface and ultimately the structural section. {note}
−
−### Air content has a direct inverse relationship with compressive strength — each percentage point of air above baseline reduces 28-day strength by approximately 3 to 5 percent. {note}
−
−# Mix Design and Concrete Classes {toc}
−
−## Required Average Compressive Strength {toc}
−
−```datasheet
−label: Concrete Class Designations Required for the Project
−type: checkbox
−options:
− - "Class A — General structural (f'c per drawings)"
− - "Class B — Foundation and below-grade elements (f'c per drawings)"
− - "Class C — Slabs on grade (f'c per drawings)"
− - "Class D — Elevated slabs (f'c per drawings)"
− - "Class E — High-strength structural elements (f'c per drawings)"
− - "Class F — Lightweight structural (f'c per drawings)"
−default: "Class A — General structural (f'c per drawings)"
−```
−
−```datasheet
−label: Minimum Specified Compressive Strength f'c — General Structural
−type: select
−unit: psi
−drawing_ref: true
−options:
− - "3000 psi"
− - "3500 psi"
− - "4000 psi"
− - "5000 psi"
− - "6000 psi"
− - "8000 psi"
− - "10000 psi"
−default: "4000 psi"
−```
−
−```datasheet
−label: Minimum Specified Compressive Strength f'c — Slabs on Grade
−type: select
−unit: psi
−drawing_ref: true
−options:
− - "3000 psi"
− - "3500 psi"
− - "4000 psi"
− - "4500 psi"
−default: "3500 psi"
−```
−
−```datasheet
−label: Minimum Specified Compressive Strength f'c — Below-Grade Walls and Foundations
−type: select
−unit: psi
−drawing_ref: true
−options:
− - "3000 psi"
− - "3500 psi"
− - "4000 psi"
− - "5000 psi"
−default: "4000 psi"
−```
−
−### The required average strength f'cr shall be determined in accordance with ACI 301-20 Section 4.2.
−
−### The Contractor shall not proportion concrete to f'c; concrete shall be proportioned to the required average strength f'cr.
−
−### The specified compressive strength f'c is a structural design value representing the minimum acceptable strength of the hardened concrete, and because concrete production has inherent statistical variability the mix must be proportioned to a required average strength f'cr higher than f'c to provide a safety margin against low individual test results. {note}
−
−## Maximum Water-to-Cementitious Materials Ratio {toc}
−
−```datasheet
−label: Maximum w/cm — General Structural Concrete (non-exposed interior)
−type: radio
−options:
− - "0.60 — Dry interior, no durability concerns (F0, S0, W0, C0)"
− - "0.55 — General commercial (moderate exposure)"
− - "0.50 — F1 freeze-thaw or C1 chloride exposure"
− - "0.45 — F2 deicing chemical or C2 chloride exposure"
− - "0.40 — W2 low permeability required; severe sulfate (S2)"
−default: "0.55 — General commercial (moderate exposure)"
−```
−
−### The Engineer of Record shall determine the required maximum w/cm for each exposure class based on ACI CODE-318-25 Table 19.3.3.
−
−### The Contractor shall not exceed the specified maximum w/cm under any circumstances; adding water at the job site to increase slump increases the w/cm and is grounds for rejection of the batch.
−
−### The maximum w/cm governs concrete durability. {note}
−
−## Slump and Workability {toc}
−
−```datasheet
−label: Slump Before Superplasticizer Addition
−type: range
−unit: in
−options:
− min: 1
− max: 5
− step: 0.5
−default: 4
−```
−
−```datasheet
−label: Slump After Superplasticizer Addition (if HRWRA used)
−type: range
−unit: in
−options:
− min: 5
− max: 9
− step: 0.5
−default: 7
−```
−
−### Slump shall be selected to allow proper placement and consolidation without segregation or bleeding.
−
−### Higher slump shall be achieved by adjusting admixture dosage, not by increasing water content.
−
−### Maximum slump at point of discharge shall be as specified above.
−
−### Concrete delivered with slump exceeding the maximum shall be rejected, and the Contractor shall not add water to reduce slump.
−
−### Where pumpability is required, the concrete producer shall proportion the mix for pumpability within the specified slump range, and the Contractor shall not request water additions to improve pump performance.
−
−### Slump is the primary field measure of concrete workability. {note}
−
−## Concrete Temperature at Delivery {toc}
−
−```datasheet
−label: Minimum Concrete Temperature at Delivery
−type: select
−unit: "°F"
−options:
− - "50°F (no cold weather precautions anticipated)"
− - "55°F (cold weather anticipated, per ACI 306R)"
−default: "50°F (no cold weather precautions anticipated)"
−```
−
−```datasheet
−label: Maximum Concrete Temperature at Delivery
−type: select
−unit: "°F"
−options:
− - "90°F (standard)"
− - "80°F (mass elements or hot weather — reduces thermal cracking risk)"
− - "75°F (critical mass concrete or high-reactivity mixes)"
−default: "90°F (standard)"
−```
−
−### Concrete temperature at point of delivery shall be measured in accordance with ASTM C1064/C1064M.
−
−### Where ambient temperature at time of placement is anticipated to exceed 90°F, or where concrete temperature is at risk of exceeding the maximum, the Contractor shall implement hot weather concreting procedures per ACI 305R-20.
−
−### The Contractor shall notify the Engineer at least 48 hours before placements at risk of exceeding the maximum concrete temperature.
−
−## Lightweight Concrete {toc}
−
−```datasheet
−label: Lightweight Concrete Required
−type: radio
−options:
− - "Not required — normal weight aggregate throughout"
− - "Required — see structural drawings for density and strength"
−default: "Not required — normal weight aggregate throughout"
−```
−
−```datasheet
−label: Unit Weight — Lightweight Concrete
−type: select
−unit: "pcf"
−drawing_ref: true
−options:
− - "Not applicable"
− - "90–100 pcf — low density"
− - "100–110 pcf — moderate density"
− - "110–120 pcf — structural lightweight"
−default: "Not applicable"
−```
−
−### Where lightweight structural concrete is required, the mix shall be designed using lightweight aggregates conforming to ASTM C330/C330M.
−
−### The equilibrium density and specified compressive strength shall be as shown on the structural drawings.
−
−### Lightweight aggregate shall be pre-wetted in accordance with the aggregate supplier's recommendations to prevent absorption of mixing water after batching.
−
−### Pre-wetting prevents a rapid slump loss and apparent workability reduction that would otherwise lead to field water additions. {note}
−
−# Formwork {toc}
−
−## Design and Engineering {toc}
−
−### Formwork shall be designed, engineered, and constructed to support all dead and live loads incident to the work, including the full weight of fresh concrete, construction loads, and any lateral loads from concrete pressure and wind, without excessive deflection or failure.
−
−### Formwork design shall be performed by a registered professional engineer licensed in the jurisdiction of the project, in accordance with ACI 347R-14 and applicable building codes.
−
−### The Contractor bears full responsibility for formwork safety and performance; the Engineer of Record's review of formwork drawings is limited to confirming that loads imposed on the structure are as assumed in the structural design and does not extend to approval of the formwork system design. {note}
−
−## Formwork Materials {toc}
−
−```datasheet
−label: Slab Soffit Form Material
−type: radio
−options:
− - "Plywood (structural-grade)"
− - "Metal deck serving as permanent form"
− - "Precast or proprietary stay-in-place form"
− - "Custom / other"
−default: "Plywood (structural-grade)"
−```
−
−```datasheet
−label: Wall and Column Form Material
−type: radio
−options:
− - "Plywood-faced wood forms"
− - "Steel forms"
− - "Aluminum forms"
− - "Proprietary forming system"
−default: "Plywood-faced wood forms"
−```
−
−## Formwork Surface Preparation {toc}
−
−```datasheet
−label: Form Release Agent
−type: radio
−options:
− - "Petroleum-based form oil"
− - "Water-based (low-VOC) form release agent"
− - "Reactive (chemically-bonding) release agent"
−default: "Water-based (low-VOC) form release agent"
−```
−
−### All form surfaces that will be in contact with concrete shall be clean and free of dirt, sawdust, mortar droppings, ice, snow, and standing water at the time of concrete placement.
−
−### Form release agent (form oil) shall be applied to all form surfaces before placing reinforcement to prevent adhesion of concrete.
−
−### Form release agents shall be compatible with any specified surface treatment, coating, or adhesive that will be applied to the finished surface.
−
−### Silicone-based or reactive release agents shall not be used where paint, epoxy, or adhesive bonding is required.
−
−## Form Ties {toc}
−
−### Form ties shall be of sufficient strength to resist the hydrostatic pressure of fresh concrete at the specified placement rate.
−
−### Tie spacing and size shall be determined by the formwork designer.
−
−### After form removal, tie break-backs shall be recessed at least 3/4 in. from the concrete surface and the recess shall be patched as specified under Repair of Defects.
−
−### Snap ties, she-bolts, and coil-rod tie systems are all acceptable. {note}
−
−## Formwork Deflection {toc}
−
−### Soffit forms for elevated slabs and beams shall be cambered to offset the anticipated deflection under the weight of fresh concrete, unless the structural design has accounted for formwork deflection and the resulting slab thickness variation.
−
−### The Contractor shall verify that camber and shoring stiffness provide a final slab thickness that meets the tolerances of ACI 117-10.
−
−### Uncompensated formwork deflection is a common cause of slab thickness being less than specified and of visual waviness in finished slab soffits. {note}
−
−## Shoring and Reshoring {toc}
−
−```datasheet
−label: Minimum Age Before Slab Soffit Shore Removal (without field break evidence)
−type: select
−unit: days
−options:
− - "7 days (Type III cement or accelerator, f'c ≥ 70% verified)"
− - "10 days (general — Type I/II cement, moderate temperature)"
− - "14 days (cold weather or SCM-heavy mixes)"
− - "Per field-cured cylinder breaks — 75% of f'c required"
−default: "Per field-cured cylinder breaks — 75% of f'c required"
−```
−
−### Multi-story shoring and reshoring shall be designed by the formwork engineer to account for accumulated construction loads in accordance with ACI 347R-14.
−
−### Shoring shall not be removed until concrete has achieved sufficient strength to carry the imposed loads without distress.
−
−### Where the Contractor proposes to remove shoring at ages earlier than the minimums of ACI 347R-14, field-cured cylinder break results shall demonstrate that the concrete has reached the design service strength under the actual temperature history of the pour.
−
−## Form Removal — Vertical Elements {toc}
−
−```datasheet
−label: Minimum Age Before Vertical Form Removal
−type: select
−unit: hours
−options:
− - "12 hours (warm weather, Type I/II, no SCM)"
− - "24 hours (standard)"
− - "48 hours (cold weather or SCM mixes)"
− - "72 hours (winter concreting)"
−default: "24 hours (standard)"
−```
−
−### The minimum age for vertical form removal shall be determined by the ambient temperature and the concrete's strength development.
−
−### Column and wall forms shall not be removed until the concrete can support its own weight and surface temperatures will not cause thermal shock.
−
−### Vertical formwork (walls, columns, and beam sides) may be removed earlier than soffit forms because the concrete self-supports upon removal. {note}
−
−# Reinforcement Coordination {toc}
−
−## Reinforcing steel procurement, detailing, fabrication, and placement, including bar sizes, grades, cover requirements, and splicing, are governed by [[sync/concrete-reinforcement]]. {note}
−
−```datasheet
−label: Concrete Cover to Reinforcement — Exposed to Weather or in Contact with Ground
−type: select
−unit: in
−drawing_ref: true
−options:
− - "3 in — bars #6 and larger (cast against earth)"
− - "2 in — bars #5 and smaller (cast against earth)"
− - "2 in — bars #6 and larger (exposed to weather)"
− - "1-1/2 in — bars #5 and smaller (exposed to weather)"
−default: "2 in — bars #6 and larger (exposed to weather)"
−```
−
−```datasheet
−label: Concrete Cover to Reinforcement — Not Exposed to Weather (Interior)
−type: select
−unit: in
−drawing_ref: true
−options:
− - "1-1/2 in — slabs and walls"
− - "1-1/2 in — beams and columns"
− - "3/4 in — slabs and joists where f'c ≥ 3000 psi"
−default: "1-1/2 in — slabs and walls"
−```
−
−## The Contractor shall verify, before any concrete placement proceeds, that reinforcing steel is in place in accordance with approved shop drawings, that cover is correctly maintained by listed plastic chairs, continuous bar supports, or other approved supports, and that reinforcement, embeds, and conduits are not displaced during placement and consolidation.
−
−## Minimum concrete cover for reinforcing steel shall be as shown on the structural drawings and shall conform to ACI CODE-318-25 Table 20.6.1.3.
−
−## The Contractor shall not accept field substitutions or modifications to reinforcement without written direction from the Engineer of Record.
−
−## Tradesmen shall not use reinforcing bars as stepping or pulling points in a manner that displaces the bar from its designed position.
−
−## Before placing concrete in any element, the Contractor's superintendent and the testing agency technician shall jointly verify that reinforcement type, size, spacing, and cover meet the approved shop drawings.
−
−# Placement and Consolidation {toc}
−
−## Pre-Placement Inspection {toc}
−
−### Immediately before placing concrete, the Contractor shall inspect and verify that formwork is tightly constructed and braced, all loose material is removed, reinforcing steel and embeds are positioned per approved drawings, anchor bolts and sleeves are templated and secured, the subgrade is damp (not muddy) for slabs on grade, formed surfaces are coated with release agent, and openings for cleanouts are closed.
−
−### In cold weather, ice and snow shall be absent from all surfaces.
−
−### Concrete shall not be placed until the pre-placement inspection conditions are satisfactory and the testing agency technician is on-site.
−
−## Placement Equipment and Methods {toc}
−
−```datasheet
−label: Primary Concrete Placement Method
−type: radio
−options:
− - "Pump — boom pump or line pump"
− - "Crane and bucket"
− - "Direct chute from truck"
− - "Conveyor or buggy"
−default: "Pump — boom pump or line pump"
−```
−
−### The placement method shall not cause segregation, excessive velocity, or loss of entrained air that compromises the mix properties at the point of placement.
−
−### Pump lines, chutes, and elephant trunks shall direct concrete to its final location without permitting free fall that exceeds 4 feet for reinforced concrete or 5 feet for mass placements, unless a segregation-prevention device is used.
−
−### Pump lines shall be primed with a mortar slurry of the same cement content as the concrete, and the priming slurry shall be discarded and not incorporated into structural elements.
−
−### Pump lines shall not be cleaned by injecting water back through the line into a placed element.
−
−## Lift Height {toc}
−
−```datasheet
−label: Maximum Lift Height — Walls
−type: select
−unit: in
−options:
− - "12 in — congested reinforcing or limited vibrator access"
− - "18 in — standard"
− - "24 in — with Engineer approval and vibration plan"
−default: "18 in — standard"
−```
−
−### Concrete in walls shall be placed in lifts not exceeding 18 inches to prevent lateral pressure exceeding the formwork design load and to allow effective vibration consolidation.
−
−### The vibrator shall be able to penetrate the full depth of each lift and into the preceding lift by approximately 6 inches to knit the layers.
−
−### Slabs and footings may be placed in a single lift unless the Engineer directs otherwise.
−
−## Consolidation {toc}
−
−```datasheet
−label: Vibration Method
−type: radio
−options:
− - "Internal (immersion) vibrator — standard"
− - "Form-attached external vibrator — thin walls with congested reinforcing"
− - "Combination — internal and external"
− - "Self-consolidating concrete (SCC) — no vibration required; requires Engineer approval"
−default: "Internal (immersion) vibrator — standard"
−```
−
−```datasheet
−label: Internal Vibrator Head Diameter
−type: select
−unit: in
−options:
− - "1 in — congested reinforcing, thin sections"
− - "1-1/2 in — column ties and wall reinforcing"
− - "2 in — standard structural elements"
− - "3 in — walls and foundations, moderate congestion"
− - "4–6 in — mass foundations and large walls"
−default: "2 in — standard structural elements"
−```
−
−### All concrete shall be consolidated immediately after placement by internal mechanical vibration, except where the Engineer specifically approves self-consolidating concrete (SCC) that is designed to flow without vibration.
−
−### Internal vibrators shall be inserted vertically at regular intervals not exceeding 1.5 times the vibrator's radius of action (typically 18 to 24 inches for a 2-inch head).
−
−### The vibrator shall be inserted quickly, held steady for 5 to 15 seconds until air bubbles cease rising, then slowly withdrawn at a rate that does not leave a hole.
−
−### The vibrator shall not be dragged horizontally through the concrete, used to move concrete laterally, used as a rodding tool, or allowed to contact reinforcing steel for extended periods.
−
−### Vibrator insertion points shall overlap to eliminate unvibrated zones.
−
−### Brief incidental contact between the vibrator and reinforcing steel is unavoidable and harmless, but re-vibrating the same location to move concrete is not acceptable. {note}
−
−### Re-vibration of concrete in walls is permitted up to 45 to 60 minutes after placement, before initial set, provided the vibrator sinks freely into the concrete under its own weight.
−
−### Vibration is the single most important factor in achieving dense, void-free concrete; unconsolidated concrete characteristically shows honeycombing, cold joints, and cold layers that are among the most difficult structural defects to repair, and re-vibration can close settlement cracks and voids that form as concrete bleeds. {note}
−
−## Prohibitions on Water Addition {toc}
−
−### No water shall be added to concrete at any time after the initial water was charged at the plant.
−
−### Truck operators shall not add water without the Contractor superintendent's written authorization, and the Contractor superintendent shall not authorize water addition.
−
−### Loads to which water was added shall be rejected.
−
−### If additional workability is needed, the Contractor shall contact the concrete producer to adjust the admixture dosage and deliver a fresh load.
−
−### Water addition voids the approved mix design, increases the w/cm, reduces strength, and increases shrinkage. {note}
−
−## Intermittent Placement — Avoiding Cold Joints {toc}
−
−### Concrete shall be placed continuously within each element or lift, and the Contractor shall plan the placement rate to ensure that each layer is covered before initial set occurs, accounting for delivery time, transport distance, temperature, and admixture dosage.
−
−### If placement is interrupted for any reason that risks a cold joint, the Contractor shall immediately notify the Engineer, and the Engineer shall determine whether to proceed or to treat the interruption as a construction joint.
−
−### A cold joint forms when a layer of concrete has advanced beyond initial set before the next layer is placed against it, creating planes of weakness and potential leakage paths. {note}
−
−# Joints {toc}
−
−## Construction Joints {toc}
−
−```datasheet
−label: Construction Joint Surface Treatment
−type: radio
−options:
− - "Roughened by mechanical scarification or sandblasting to 1/4 in amplitude (preferred)"
− - "Green cut with water jet before final set (exposed aggregate surface)"
− - "Bonding agent — per Engineer approval and product data"
−default: "Roughened by mechanical scarification or sandblasting to 1/4 in amplitude (preferred)"
−```
−
−### Construction joints are structural features that shall be located as shown on the drawings or in locations approved by the Engineer.
−
−### Unauthorized construction joints shall not be created without prior written approval.
−
−### Before placing concrete against a hardened construction joint, the surface shall be cleaned of all laitance, loose aggregate, and debris, thoroughly wetted, and kept damp but free of standing water.
−
−### Where a bonding agent is used, it shall be applied and the concrete placed within the manufacturer's open time.
−
−### A key or roughened surface is the standard for monolithic structural joints; reliance on bonding agents alone is not recommended for shear-critical joints. {note}
−
−## Isolation Joints {toc}
−
−```datasheet
−label: Isolation Joint Filler Material
−type: radio
−drawing_ref: true
−options:
− - "Closed-cell polyethylene foam filler, compressible"
− - "Asphalt-impregnated fiber filler"
−default: "Closed-cell polyethylene foam filler, compressible"
−```
−
−### Isolation joints shall be full-depth pre-molded joint filler as shown on the drawings.
−
−### Isolation joints separate the slab from fixed elements — columns, walls, and equipment pads — to allow differential movement without restraint cracking. {note}
−
−## Contraction Joints (Control Joints) {toc}
−
−```datasheet
−label: Contraction Joint Method
−type: radio
−options:
− - "Saw cut — conventional wet saw"
− - "Saw cut — early-entry saw"
− - "Tooled joint during finishing"
− - "Installed insert — plastic or hardboard"
−default: "Saw cut — conventional wet saw"
−```
−
−```datasheet
−label: Contraction Joint Depth
−type: radio
−options:
− - "1/4 of slab thickness (minimum)"
− - "1/3 of slab thickness (recommended for crack control)"
−default: "1/4 of slab thickness (minimum)"
−```
−
−### Contraction joints in slabs on grade shall be formed by saw cutting or by installed plastic or hardboard inserts as shown on the contract drawings.
−
−### Saw-cut joints shall be cut within 4 to 12 hours after placement, with the precise timing established by the Contractor based on the concrete mix, ambient conditions, and concrete temperature to ensure the cut is made before uncontrolled cracking initiates but after the aggregate is no longer raveled by the saw.
−
−### Joint spacing for slabs on grade shall be as shown on the contract drawings.
−
−### Contraction joints provide stress-relief planes to control the location of shrinkage cracks; a common guideline is joint spacing in feet not exceeding 2 to 3 times the slab thickness in inches, with closer spacing for oversized bays, high-shrinkage mixes, or rapid drying conditions. {note}
−
−## Expansion Joints {toc}
−
−```datasheet
−label: Expansion Joint Filler and Sealant
−type: radio
−drawing_ref: true
−options:
− - "Pre-molded filler with elastomeric sealant — standard"
− - "Pre-molded filler with compression seal"
− - "Armored edge protection — heavy-traffic slabs"
−default: "Pre-molded filler with elastomeric sealant — standard"
−```
−
−### The expansion joint width, filler type, and sealant shall be as shown on the contract drawings.
−
−### Expansion joints shall be continuous through the full depth and thickness of the element and shall not be bridged by reinforcing bars or embeds unless specifically detailed as a structural sliding connection.
−
−### Expansion joints accommodate thermal movement between adjacent structural bays or between the structure and surrounding paving. {note}
−
−# Finishes {toc}
−
−## Formed Surfaces {toc}
−
−### Rough Form Finish {toc}
−
−```datasheet
−label: Rough Form Finish Required
−type: radio
−options:
− - "Yes — unexposed structural surfaces"
− - "No — all surfaces receive a higher-quality finish"
−default: "Yes — unexposed structural surfaces"
−```
−
−#### Rough form finish is the default for unexposed formed surfaces that will be concealed by backfill, other materials, or finishes, and requires no work beyond form removal; tie holes shall be patched per Repair of Defects.
−
−### Smooth Form Finish {toc}
−
−```datasheet
−label: Smooth Form Finish Surface Quality
−type: radio
−options:
− - "Form marks and seams permitted; tie holes patched"
− - "Ground flush — all fins, ridges, and seams removed after form stripping"
−default: "Form marks and seams permitted; tie holes patched"
−```
−
−#### Smooth form finish shall be achieved with plywood or steel forms that produce a uniform surface.
−
−#### Minor fins, seams, and form marks shall be ground flush.
−
−#### Tie holes in smooth form finish surfaces shall be patched.
−
−#### Honeycombing, cold joints, or discoloration of more than minor extent shall be subject to rejection or repair as determined by the Engineer.
−
−#### Smooth form finish is the standard for exposed formed surfaces visible in the completed building but not designated architectural concrete. {note}
−
−## Unformed Surfaces (Slabs and Footings) {toc}
−
−```datasheet
−label: Slab on Grade Finish Type
−type: radio
−options:
− - "Screeded — slab to receive topping or fill"
− - "Floated — slab to receive floor covering, coating, or no topping"
− - "Troweled — slab to be left exposed or receive thin coating"
− - "Broom finish — exterior slabs requiring slip resistance"
−default: "Troweled — slab to be left exposed or receive thin coating"
−```
−
−### Screeded Finish {toc}
−
−#### A screeded finish shall be struck off level with the screed, tamped to bring aggregate below the surface, and left without further work.
−
−#### A screeded finish is used where the surface will receive topping, fill, or insulation and appearance is not important. {note}
−
−### Floated Finish {toc}
−
−#### A floated finish shall be screeded, then floated with a bull float or darby to embed aggregate, remove ridges, and fill low spots.
−
−#### Power floating shall follow hand floating when the concrete has hardened sufficiently that the machine does not sink more than 1/8 inch under the weight of the operator.
−
−#### A floated finish is the standard for slabs that will receive floor coverings, coatings, or toppings. {note}
−
−### Troweled Finish {toc}
−
−```datasheet
−label: Floor Flatness and Levelness Requirements
−type: radio
−options:
− - "ACI 117 conventional tolerance — no special FF/FL required"
− - "FF25/FL20 — typical commercial floor"
− - "FF35/FL25 — better commercial floor with floor covering"
− - "FF50/FL35 — high-tolerance floor, narrow-aisle warehouse"
− - "Superflat FF100+ — per separate specification and pre-installation survey"
−default: "FF25/FL20 — typical commercial floor"
−```
−
−#### A troweled finish is required for concrete floor slabs that will be exposed to foot traffic, vehicle traffic, or that will serve as a finish floor.
−
−#### After power floating, the surface shall be power troweled with progressively reduced blade angle until the surface is dense, smooth, and free of trowel marks.
−
−#### Troweling shall not be started until the surface has lost its sheen, and water or cement shall not be applied to the surface to aid troweling.
−
−#### Floor flatness (FF) and floor levelness (FL) shall be measured per ASTM E1155.
−
−#### Where F-number requirements are specified, the measurement protocol (random traffic floor vs. defined traffic floor), the number of measurements, and the acceptance criteria shall be established before placement.
−
−#### Hard troweling while bleed water is still rising to the surface traps the water below a dense skin, creating dusting and delamination — the most common defect in interior concrete floor slabs. {note}
−
−### Broom Finish {toc}
−
−```datasheet
−label: Broom Finish Texture
−type: radio
−options:
− - "Light broom — sidewalks and normal exterior slabs"
− - "Medium broom — loading docks and light vehicle areas"
− - "Heavy broom — ramps and high-slip-resistance required areas"
−default: "Light broom — sidewalks and normal exterior slabs"
−```
−
−#### Exterior slabs, sidewalks, loading docks, ramps, and any slab subject to precipitation shall receive a light broom finish drawn perpendicular to the primary direction of foot or vehicle traffic.
−
−#### Broom texture shall be applied after floating, when the concrete has stiffened sufficiently to hold the texture without tearing.
−
−#### Heavy broom finish is appropriate for ramps and where additional slip resistance is required. {note}
−
−# Curing and Protection {toc}
−
−## Curing shall begin immediately after finishing operations are complete and shall continue uninterrupted for the full required curing period, in accordance with ACI 308R-16.
−
−## Curing is the maintenance of adequate moisture and temperature in freshly placed concrete to allow cement hydration to continue; poorly cured concrete achieves only 50 to 70 percent of the strength of well-cured concrete and develops a highly permeable surface zone vulnerable to freeze-thaw damage, chemical attack, and abrasion. {note}
−
−## Curing Methods {toc}
−
−```datasheet
−label: Primary Curing Method — Horizontal Surfaces
−type: radio
−options:
− - "Curing compound — liquid membrane-forming (ASTM C309 Type 1-D or Type 2)"
− - "Curing compound — white-pigmented (ASTM C309 Type 2 — hot weather)"
− - "Wet burlap with polyethylene sheeting over"
− - "Polyethylene sheeting — white for hot weather, black for cold weather"
− - "Insulated curing blankets — cold weather"
−default: "Curing compound — liquid membrane-forming (ASTM C309 Type 1-D or Type 2)"
−```
−
−```datasheet
−label: Primary Curing Method — Vertical and Overhead Formed Surfaces
−type: radio
−options:
− - "Leave forms in place for required curing period"
− - "Wet burlap wrapped and secured after form removal"
− - "Curing compound applied immediately after form removal"
−default: "Leave forms in place for required curing period"
−```
−
−### Curing compound shall conform to ASTM C309, Type 1-D (dissipating) or Type 2, and shall be applied in two passes at 90 degrees to each other at the rate recommended by the manufacturer to provide a continuous, unbroken membrane.
−
−### Curing compound shall not be applied to surfaces where adhesive bonding, paint, epoxy coatings, or additional concrete topping will be applied unless the compound is demonstrated to be compatible with or dissipates before the subsequent application.
−
−### Where compatibility of curing compound cannot be confirmed, wet curing methods shall be used.
−
−### Where wet curing is used, burlap shall be pre-soaked before application and shall be kept continuously wet during the curing period.
−
−### The burlap shall be in direct contact with the concrete surface, not bridging across it.
−
−### Burlap curing in hot and dry weather requires dedicated watering; drying of the burlap even for a few hours substantially diminishes curing effectiveness. {note}
−
−## Curing Duration {toc}
−
−```datasheet
−label: Curing Duration — Normal Conditions (50°F to 90°F ambient)
−type: select
−unit: days
−options:
− - "3 days — Type III cement or rapid-set mix"
− - "7 days — Type I/II cement (minimum for most structural elements)"
− - "10 days — elevated slabs and structural walls"
− - "14 days — below-grade elements, foundations, and SCM mixes"
−default: "7 days — Type I/II cement (minimum for most structural elements)"
−```
−
−### Mixes containing significant proportions of fly ash or slag cement develop strength more slowly than plain portland cement mixes and shall be cured longer than plain portland cement mixes.
−
−### The long-term durability benefits of SCMs depend on extended curing to develop the pozzolanic reaction, so the curing period for SCM mixes shall not be reduced because they appear strong enough. {note}
−
−## Hot Weather Concreting {toc}
−
−```datasheet
−label: Hot Weather Concreting Precautions (when applicable)
−type: checkbox
−options:
− - "Ice substituted for portion of mix water"
− - "Aggregate cooling"
− - "Reduced truck haul time (< 60 min total)"
− - "Retarding admixture (ASTM C494 Type B or D)"
− - "Evaporation retardant applied to fresh slab surface"
− - "Nighttime or early-morning placement"
− - "Wind screens at slab edges"
−default: "Retarding admixture (ASTM C494 Type B or D)"
−```
−
−### When the ambient temperature is at or above 90°F, or when evaporation rate exceeds 0.20 lb/ft²/hr (calculate per ACI 305R-20 Figure 2.1.5 from temperature, relative humidity, and wind speed), the Contractor shall implement hot weather concreting procedures.
−
−### Hot weather concreting procedures shall include one or more of the following: cooling of mix water with ice, chilling of aggregates with water, reducing haul time and truck capacity to limit time from batching to placement, using a retarding admixture, placing in the cooler parts of the day, providing wind breaks to reduce evaporation, and applying an evaporation retardant (fog-mist or monomolecular film) to the slab surface during the period between screeding and final finishing.
−
−### Plastic shrinkage cracking is the most visible manifestation of inadequate hot weather concreting; plastic shrinkage cracks do not recover on their own, typically extend through a significant fraction of the slab thickness, and prevention is the only effective strategy. {note}
−
−## Cold Weather Concreting {toc}
−
−```datasheet
−label: Cold Weather Protection Method
−type: checkbox
−options:
− - "Heated enclosure — tenting with propane or electric heat"
− - "Insulating blankets — concrete and forms"
− - "Accelerating admixture — non-chloride (ASTM C494 Type C)"
− - "Heated mix water"
− - "Heated aggregates"
− - "Not applicable — no cold weather anticipated"
−default: "Not applicable — no cold weather anticipated"
−```
−
−```datasheet
−label: Cold Weather — Minimum Concrete Temperature at Time of Placement
−type: select
−unit: "°F"
−options:
− - "Not applicable"
− - "55°F — sections 12–36 in thick"
− - "60°F — sections 6–12 in thick"
− - "65°F — sections less than 6 in thick"
−default: "Not applicable"
−```
−
−### Cold weather concreting provisions apply when the air temperature has fallen below 40°F or is expected to fall below 40°F during the protection period, in accordance with ACI 306R-16.
−
−### Fresh concrete shall be protected from freezing until it achieves a compressive strength of at least 500 psi.
−
−### Minimum concrete temperature at delivery shall be increased per ACI 306R-16 Table 3.1 based on section thickness, with thinner sections requiring higher delivery temperatures because they lose heat faster.
−
−### The Contractor shall provide adequate ventilation wherever combustion heaters are used and shall monitor CO levels.
−
−### Concrete shall not be cooled more than 5°F per hour in any surface layer, and the differential between the core and the surface of mass elements shall not exceed 35°F.
−
−### Concrete that freezes before reaching 500 psi may be permanently damaged regardless of subsequent warming. {note}
−
−### Carbon monoxide from combustion heaters is a serious safety hazard in enclosed forms and enclosures; forced-air propane heaters that exhaust to the outside are preferred over open-flame heaters inside the enclosure. {note}
−
−### Rapid surface cooling after removal of insulation causes thermal gradient cracking that is not related to freeze damage and can occur even after the concrete has reached design strength. {note}
−
−# Tolerances {toc}
−
−## Dimensional tolerances for all cast-in-place concrete work shall comply with ACI 117-10 (Reapproved 2015).
−
−## Work outside tolerance shall be evaluated by the Engineer for structural acceptability and remedial action shall be taken as directed.
−
−## Vertical Alignment (Plumb) {toc}
−
−```datasheet
−label: Maximum Out-of-Plumb Tolerance — Walls and Columns
−type: select
−unit: in
−options:
− - "3/8 in per 10 ft, max 3/4 in in 30 ft (exposed in completed structure)"
− - "1/2 in per 10 ft, max 1 in in 30 ft (unexposed)"
−default: "3/8 in per 10 ft, max 3/4 in in 30 ft (exposed in completed structure)"
−```
−
−## Level and Grade {toc}
−
−```datasheet
−label: Maximum Deviation from Level — Slab-on-Grade Top Surface
−type: select
−unit: in
−options:
− - "3/8 in under 10-ft straightedge (no special FF requirement)"
− - "Per specified F-number (measured per ASTM E1155)"
−default: "3/8 in under 10-ft straightedge (no special FF requirement)"
−```
−
−```datasheet
−label: Maximum Deviation from Level — Elevated Slab Soffit
−type: select
−unit: in
−options:
− - "3/8 in under 10-ft straightedge"
− - "1/2 in under 10-ft straightedge"
−default: "3/8 in under 10-ft straightedge"
−```
−
−## Cross-Section Dimensions {toc}
−
−```datasheet
−label: Tolerance on Member Thickness (Slabs, Walls)
−type: select
−unit: in
−options:
− - "-3/8 in, +3/8 in — formed elements"
− - "-3/8 in, +1/2 in — slabs on grade"
−default: "-3/8 in, +3/8 in — formed elements"
−```
−
−```datasheet
−label: Tolerance on Column and Beam Cross-Section
−type: select
−unit: in
−options:
− - "-1/4 in, +3/8 in"
− - "-1/4 in, +1/2 in (large sections over 24 in)"
−default: "-1/4 in, +3/8 in"
−```
−
−## Variation from Specified Location {toc}
−
−```datasheet
−label: Tolerance on Plan Location of Columns and Walls
−type: select
−unit: in
−options:
− - "1 in — in any direction from design location"
− - "3/4 in — critical alignment requirement"
−default: "1 in — in any direction from design location"
−```
−
−## Openings and Inserts {toc}
−
−```datasheet
−label: Anchor Bolt Group Location Tolerance
−type: select
−unit: in
−drawing_ref: "structural steel shop drawings"
−options:
− - "1/8 in within the group, 1/4 in on group centerline (standard for structural steel)"
−default: "1/8 in within the group, 1/4 in on group centerline (standard for structural steel)"
−```
−
−### Embedded items, sleeves, anchor bolts, and openings shall be located within the tolerances shown on the structural drawings or, where not shown, within ±1/2 in. of the design location in plan.
−
−### Anchor bolt groups for column base plates shall be set using a template secured to the formwork to maintain the pattern tolerance required by the structural steel fabricator.
−
−### Anchor bolt misalignment is a frequent cause of costly steel column erection delays. {note}
−
−# Field Testing and Quality Control {toc}
−
−## Testing Frequency {toc}
−
−```datasheet
−label: Compressive Strength Test Frequency
−type: radio
−options:
− - "One set per 50 cy or fraction thereof, minimum one set per element, minimum one set per day of placement"
− - "One set per 100 cy — high-volume continuous pours (mat foundations)"
− - "One set per 150 cy — with Engineer approval for known consistent mixes"
−default: "One set per 50 cy or fraction thereof, minimum one set per element, minimum one set per day of placement"
−```
−
−### Field testing shall be performed by the Owner's testing agency on concrete delivered to the project.
−
−### The Contractor shall notify the testing agency of each pour date and time with a minimum 24-hour advance notice.
−
−### Each strength test set shall consist of a minimum of four cylinders: two tested at 7 days for early strength indication and two tested at 28 days for acceptance.
−
−### Cylinders for acceptance testing shall be standard-cured (moist-cured at 73 ± 3°F) in accordance with ASTM C31/C31M.
−
−## Fresh Concrete Tests {toc}
−
−### At each sampling, the testing agency shall measure and record the following:
−
−- Temperature per ASTM C1064/C1064M
−- Slump per ASTM C143/C143M
−- Air content per ASTM C231/C231M (or ASTM C173/C173M for lightweight concrete)
−- Unit weight per ASTM C138/C138M
−- Time of sampling, time of batching (from ticket), air and concrete temperature
−
−```datasheet
−label: Fresh Concrete Tests Required at Each Sampling
−type: checkbox
−options:
− - "Temperature (ASTM C1064)"
− - "Slump (ASTM C143)"
− - "Air content — pressure method (ASTM C231)"
− - "Air content — volumetric method (ASTM C173) — lightweight only"
− - "Unit weight / yield (ASTM C138)"
− - "Time of batching from delivery ticket"
−default: "Temperature (ASTM C1064)"
−```
−
−## Acceptance Criteria — Compressive Strength {toc}
−
−### The strength of a concrete mix is considered satisfactory when both of the following conditions are met simultaneously, in accordance with ACI CODE-318-25 Section 26.12.3: {note}
−
−1. Each arithmetic average of any three consecutive strength test results equals or exceeds f'c.
−2. No individual strength test result (average of two 28-day cylinders) falls below f'c by more than 500 psi when f'c ≤ 5000 psi, or below 0.90 × f'c when f'c > 5000 psi.
−
−```datasheet
−label: Response to Low Strength Test Results
−type: radio
−options:
− - "Evaluate per ACI 318-25 Section 26.12.4 — core testing and Engineer evaluation"
− - "Immediate review of mix, batching, and delivery records; Engineer notification within 24 hours"
−default: "Immediate review of mix, batching, and delivery records; Engineer notification within 24 hours"
−```
−
−### When both acceptance conditions are failed, the concrete is presumed defective and core testing per ACI 318-25 Section 26.12.4 shall be required.
−
−### The Contractor shall not wait until 28-day results are received before investigating a strength trend that is already visible at 7 days.
−
−### Failure of Condition 1 alone indicates the mix average is trending low and the Contractor shall investigate and adjust, while failure of Condition 2 alone indicates an outlier or specific batch problem; a 7-day cylinder strength of approximately 65 to 75 percent of the 28-day strength is typical for Type I/II portland cement, and a 7-day result significantly below this range warns that the 28-day result may fall short of f'c. {note}
−
−## Acceptance Criteria — Fresh Concrete {toc}
−
−### Any batch of concrete in which fresh test results exceed the limits below shall be rejected and returned to the plant, and no portion of the rejected batch shall be placed in the work:
−
−- Slump exceeds specified maximum slump
−- Air content is outside specified range by more than 1.5 percentage points
−- Concrete temperature exceeds specified maximum or is below specified minimum
−- Delivery ticket shows elapsed time from batching exceeds 90 minutes or drum has exceeded 300 revolutions of mixing
−
−### The testing agency shall immediately notify the Contractor and Engineer when a rejection criterion is triggered.
−
−### The Contractor shall provide the replacement load without interrupting the pour where possible; if interruption causes a cold-joint risk, the Engineer shall determine how to proceed.
−
−## In-Place Testing {toc}
−
−### In-place strength estimation may be used as a supplemental measure where 28-day cylinder results are low or structural loads must be applied before 28-day results are available, using rebound hammer per ASTM C805/C805M, penetration resistance per ASTM C803/C803M, or maturity method per ASTM C1074/C1074M.
−
−### In-place test results shall be correlated to standard cylinder data for the specific mix.
−
−### In-place methods are supplemental and correlational, not substitutes for core testing or standard cylinders for acceptance decisions. {note}
−
−## Core Testing {toc}
−
−### Where compressive strength results indicate that an element may contain defective concrete, the Engineer may require extraction and testing of cores per ASTM C42/C42M.
−
−### Cores shall not be extracted before 28 days unless early stripping or loading requires immediate evaluation.
−
−### Concrete in an area represented by a core is considered structurally adequate if the average of three cores in that area is at least 85 percent of f'c and no single core is below 75 percent of f'c, in accordance with ACI CODE-318-25 Section 26.12.4.3.
−
−### Core locations and testing procedures shall be determined by the Engineer.
−
−# Repair of Defects {toc}
−
−## Defects discovered after form removal shall be reported immediately to the Engineer.
−
−## No repair shall be undertaken without the Engineer's review and written direction.
−
−## Concealing defects behind coatings or unauthorized patching before Engineer review is grounds for rejection of the element.
−
−## Not all defects require repair, and not all defects can be structurally repaired. {note}
−
−## Surface Blemishes — Minor {toc}
−
−### Minor blemishes in exposed-to-view surfaces that are cosmetically objectionable may be filled with a grout mix of portland cement and fine sand at approximately 1:1.5 ratio, with water added to a stiff consistency, after thoroughly pre-wetting the surface.
−
−### Form-oil stains or excessively smoothed (burned) areas shall be mechanically abraded to open the surface before patching.
−
−### Minor surface blemishes include small bug holes (air voids less than 1/4 in. diameter), small form-joint ridges, and surface discoloration from form release agent; dry-packing of form-oil stains or burned areas is not effective. {note}
−
−## Honeycombing {toc}
−
−```datasheet
−label: Honeycombing Repair Method
−type: radio
−options:
− - "Surface patching with dry-pack mortar (depth < 1 in, no bar exposure)"
− - "Pneumatically applied mortar (shotcrete patch) — deep voids"
− - "Epoxy injection — where compressive load path must be restored"
− - "Demolition and recast — Engineer determination"
−default: "Surface patching with dry-pack mortar (depth < 1 in, no bar exposure)"
−```
−
−### The Engineer shall determine whether honeycombing is cosmetic, repairable, or structural.
−
−### All repair areas shall be saw-cut or chipped to sound concrete with square or undercutting edges; feathered edges shall not be used.
−
−### The repair surface shall be cleaned of all loose material, pre-wetted, and the repair material applied in a manner that ensures intimate contact with the substrate.
−
−### Repair materials shall match the concrete's color, texture, and performance properties as closely as practical.
−
−### Repaired areas shall be cured not less than 7 days.
−
−### Honeycombing is incomplete consolidation where coarse aggregate shows on the surface due to mortar not filling the voids between aggregates, ranging from minor surface bugholes to deep voids that expose or undermine reinforcing steel. {note}
−
−## Tie-Hole Patching {toc}
−
−### Form tie break-backs shall be cleaned of all oil, loose concrete, and debris, recessed at least 3/4 in. from the surface, and patched with dry-pack cement mortar.
−
−### Dry-pack mortar shall be placed in layers not exceeding 3/8 in. and consolidated by rodding before each layer is added.
−
−### The tie-hole patch surface shall match the surrounding concrete texture.
−
−## Cold Joints {toc}
−
−### Cold joints in below-grade walls shall have waterproofing continuity verified per [[sync/below-grade-waterproofing]].
−
−### The Engineer shall evaluate cold joints against the structural demand at that location.
−
−### Cold joints in shear walls, columns, or beams shall be treated as requiring investigation.
−
−### Cold joints in structural elements are presumed to represent a plane of reduced shear transfer and potential leakage; cold joints in slabs on grade may be satisfactory for non-structural slabs. {note}
−
−## Cracks {toc}
−
−### Surface cracks less than 0.010 in. (10 mil) width in non-water-retaining elements shall be documented.
−
−### Cracks wider than 0.010 in. in structural elements, or any cracks in elements designated to retain liquid, shall be reported to the Engineer for evaluation and direction.
−
−### Epoxy injection per ACI 224.1R is the standard repair for structural cracks that must be re-united to restore monolithic behavior. {note}
−
−# Protection of Finished Work {toc}
−
−## Concrete surfaces shall be protected from damage by subsequent construction operations, foot traffic before adequate strength, vehicle traffic, materials storage, chemical spills, and frost.
−
−## Temporary protection coverings shall be maintained until the work can sustain imposed loads without damage.
−
−## Impact damage, oil or paint contamination, and rust staining from stored steel shall not be accepted as normal construction damage and shall be repaired at the Contractor's expense.
−
−## Protection from Foot and Vehicle Traffic {toc}
−
−```datasheet
−label: Minimum Age Before Foot Traffic on Slabs
−type: select
−unit: days
−options:
− - "1 day (Type III or accelerated mix)"
− - "3 days (Type I/II, normal conditions)"
− - "7 days (SCM mixes with slow early-strength gain)"
−default: "3 days (Type I/II, normal conditions)"
−```
−
−```datasheet
−label: Minimum Age Before Vehicle or Forklift Traffic on Slabs
−type: select
−unit: days
−options:
− - "7 days (Type I/II at normal temperatures)"
− - "14 days (SCM mixes or cold weather pours)"
− - "28 days (as a conservative default for heavily loaded vehicles)"
−default: "14 days (SCM mixes or cold weather pours)"
−```
−
−### No traffic shall be permitted on concrete floor slabs until the concrete has achieved sufficient strength to support the load without cracking, spalling, or surface damage.
−
−## Chemical Spill Protection {toc}
−
−### Concrete surfaces shall be protected from oil, acid, and other chemical spills until a permanent floor coating, sealer, or topping is in place.
−
−### Concrete floors intended to be left bare shall receive a penetrating sealer within 30 days of completion to protect against oil staining and surface dusting.
−
−# Warranty {toc}
−
−```datasheet
−label: Contractor Warranty Period
−type: select
−unit: years
−options:
− - "1 year from substantial completion"
− - "2 years from substantial completion"
−default: "1 year from substantial completion"
−```
−
−## The Contractor shall warrant concrete work against defects in materials and workmanship, including premature strength failure, excessive cracking attributable to construction practice, surface scaling from freeze-thaw damage within the specified design exposure class, and delamination of troweled surfaces, for the project warranty period.
−
−## The Engineer shall determine the cause of any defect before warranty claims are pursued.
−
−## Warranty claims arising from structural loading, unanticipated chemical exposure, or conditions not described in this specification are not covered under the Contractor's warranty unless the Contractor's work failed to meet the requirements of this standard. {note}
−
−## Concrete mix designs approved by the Engineer and placed in accordance with this specification that produce 28-day strengths meeting the acceptance criteria are not subject to warranty defect claims on the basis of strength alone; where service conditions later produce distress not anticipated by the specified exposure category, responsibility for mix redesign is a design matter, not a construction defect. {note}
+---
+title: Cast-in-Place Concrete
+category: Structural / Concrete
+description: >
+ When to use: Structural cast-in-place concrete for buildings and structures — constituent materials, mixture proportioning and qualification, exposure-class durability requirements, ready-mixed production and delivery, placement and consolidation, hot- and cold-weather concreting, field testing, and evaluation and acceptance of the hardened concrete. Applies to footings, foundations, grade beams, mat foundations, below-grade walls, slabs on grade, elevated slabs and decks, columns, beams, and structural walls on commercial, institutional, and industrial projects.
+ Not intended for: Formwork design, form materials, shoring, and form removal (see [[sync/concrete-formwork]]); reinforcement supply, placement, and concrete cover (see [[sync/concrete-reinforcement]]); curing methods and duration, surface finishing, and floor flatness and levelness (see [[sync/concrete-curing-and-finishing]]); joint type selection, joint layout, joint sealing, and waterstops (see [[sync/concrete-joints-and-waterstops]]); embedded items, bar supports, and under-slab vapor retarders (see [[sync/concrete-accessories]]); assessment and repair of hardened or deteriorated concrete (see [[sync/concrete-repair-and-restoration]]); subgrade preparation and slab-on-grade design (see [[sync/slab-on-grade]]); site paving, curbs, and sidewalks (see [[sync/concrete-paving]]); equipment pads (see [[sync/concrete-pads]]); post-tensioned concrete (see [[sync/post-tensioned-concrete]]); shotcrete (see [[sync/shotcrete]]); plant-cast precast and prestressed concrete; and mass concrete for dams and similar hydraulic structures.
+---
+
+# Scope {toc}
+
+## This standard covers the constituent materials, mixture proportioning and qualification, ready-mixed production and delivery, placement, consolidation, weather protection during placement, and evaluation and acceptance of structural cast-in-place concrete. {note}
+
+## Cast-in-place concrete is not one material but a family of proportioned mixtures, each engineered for the structural demand on a member, the exposure that member will meet in service, and the way the concrete will be delivered and placed into it. Two mixtures that both satisfy a 4000 psi design strength can behave completely differently in a freeze-thaw environment, in sulfate-bearing soil, or in a congested column cage, because strength and durability are governed by different parameters of the same mixture. {note}
+
+## The failure modes this standard controls are largely irreversible. Concrete is hidden inside formwork until stripping, it acquires its properties through reactions that cannot be interrupted and resumed, and a defective element usually cannot be corrected without demolition. Mixture qualification, delivery limits, consolidation, and field testing are therefore not administrative overhead; they are the last points at which defective work can still be stopped. {note}
+
+## Concrete and its constituent materials shall comply with ACI 301, and where structural performance is established by design, with ACI 318.
+
+## The work of the following standards is coordinated with, but not specified by, this standard. {note}
+
+- Formwork design, form materials and ties, release agents, shoring and reshoring, and form and shore removal — [[sync/concrete-formwork]].
+- Reinforcing bar supply, fabrication, placement, support, splicing, and concrete cover — [[sync/concrete-reinforcement]].
+- Curing methods and duration, surface finishing, floor flatness and levelness, and surface-defect acceptance — [[sync/concrete-curing-and-finishing]].
+- Joint type selection, joint layout and spacing, joint preparation and sealing, and waterstops — [[sync/concrete-joints-and-waterstops]].
+- Embedded plates and anchor rods, bar supports, dovetail slots, and under-slab vapor retarder placement — [[sync/concrete-accessories]].
+- Assessment and repair of hardened, deteriorated, or defective concrete — [[sync/concrete-repair-and-restoration]].
+- Subgrade preparation and structural design of slabs on grade — [[sync/slab-on-grade]].
+
+## Plant-cast precast and prestressed concrete, post-tensioned concrete, shotcrete, concrete masonry, site paving and flatwork outside the building line, equipment pads, and mass concrete for dams and similar hydraulic structures lie outside this standard. {note}
+
+# Referenced Standards {toc}
+
+## Materials, production, delivery, placement, and testing shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
+
+## Where the contract documents, the building code, or a referenced standard conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing.
+
+| Standard | Title |
+|----------|-------|
+| ACI 214R | Evaluation of Strength Test Results of Concrete |
+| ACI 301 | Specifications for Concrete Construction |
+| ACI 305R | Guide to Hot Weather Concreting |
+| ACI 306R | Guide to Cold Weather Concreting |
+| ACI 309R | Guide for Consolidation of Concrete |
+| ACI 318 | Building Code Requirements for Structural Concrete and Commentary |
+| ASTM C31/C31M | Making and Curing Concrete Test Specimens in the Field |
+| ASTM C33/C33M | Concrete Aggregates |
+| ASTM C39/C39M | Compressive Strength of Cylindrical Concrete Specimens |
+| ASTM C42/C42M | Obtaining and Testing Drilled Cores and Sawed Beams of Concrete |
+| ASTM C94/C94M | Ready-Mixed Concrete |
+| ASTM C138/C138M | Density, Yield, and Air Content of Concrete (Gravimetric) |
+| ASTM C143/C143M | Slump of Hydraulic-Cement Concrete |
+| ASTM C150/C150M | Portland Cement |
+| ASTM C157/C157M | Length Change of Hardened Hydraulic-Cement Mortar and Concrete |
+| ASTM C172/C172M | Sampling Freshly Mixed Concrete |
+| ASTM C173/C173M | Air Content of Freshly Mixed Concrete by the Volumetric Method |
+| ASTM C231/C231M | Air Content of Freshly Mixed Concrete by the Pressure Method |
+| ASTM C260/C260M | Air-Entraining Admixtures for Concrete |
+| ASTM C330/C330M | Lightweight Aggregates for Structural Concrete |
+| ASTM C494/C494M | Chemical Admixtures for Concrete |
+| ASTM C595/C595M | Blended Hydraulic Cements |
+| ASTM C618 | Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete |
+| ASTM C803/C803M | Penetration Resistance of Hardened Concrete |
+| ASTM C805/C805M | Rebound Number of Hardened Concrete |
+| ASTM C989/C989M | Slag Cement for Use in Concrete and Mortars |
+| ASTM C1017/C1017M | Chemical Admixtures for Use in Producing Flowing Concrete |
+| ASTM C1064/C1064M | Temperature of Freshly Mixed Hydraulic-Cement Concrete |
+| ASTM C1074 | Estimating Concrete Strength by the Maturity Method |
+| ASTM C1077 | Agencies Testing Concrete and Concrete Aggregates for Use in Construction |
+| ASTM C1157/C1157M | Performance Specification for Hydraulic Cement |
+| ASTM C1218/C1218M | Water-Soluble Chloride in Mortar and Concrete |
+| ASTM C1231/C1231M | Use of Unbonded Caps in Determination of Compressive Strength of Hardened Cylindrical Concrete Specimens |
+| ASTM C1240 | Silica Fume Used in Cementitious Mixtures |
+| ASTM C1260 | Potential Alkali Reactivity of Aggregates (Mortar-Bar Method) |
+| ASTM C1293 | Length Change of Concrete Due to Alkali-Silica Reaction |
+| ASTM C1567 | Potential Alkali-Silica Reactivity of Combinations of Cementitious Materials and Aggregate |
+| ASTM C1602/C1602M | Mixing Water Used in the Production of Hydraulic Cement Concrete |
+| ASTM C1610/C1610M | Static Segregation of Self-Consolidating Concrete Using Column Technique |
+| ASTM C1611/C1611M | Slump Flow of Self-Consolidating Concrete |
+| ASTM C1621/C1621M | Passing Ability of Self-Consolidating Concrete by J-Ring |
+| ASTM C1778 | Reducing the Risk of Deleterious Alkali-Aggregate Reaction in Concrete |
+| ASTM C1866/C1866M | Ground-Glass Pozzolan for Use in Concrete |
+
+# Submittals {toc}
+
+## Action Submittals {toc}
+
+### The Contractor shall submit the following for review and acceptance before concrete is ordered for the affected element:
+
+- Concrete mixture design for each mixture class, identifying every cementitious material, aggregate, admixture, and water source, the batch weights, the water-cementitious materials ratio, the design air content, the design slump or slump flow, and the exposure classes the mixture is proportioned to satisfy
+- Documentation establishing the required average compressive strength for each mixture, consisting of the production strength record and its calculated standard deviation, the trial mixture results, or both
+- Product data and certificates of conformance for each cementitious material, aggregate source, and admixture
+- Qualification data for any mixing water source other than potable water, including the solids content of reclaimed water
+- Aggregate gradation analysis and alkali-aggregate reactivity evaluation for each aggregate source
+- Placement plan for each element that cannot be placed continuously from a single position, identifying the placement sequence, the location of construction joints, the placement rate, the consolidation equipment, and the anticipated concrete and ambient temperatures
+- Hot-weather and cold-weather concreting plans covering the measures selected in the datasheet and the temperature-monitoring method
+
+```datasheet
+label: Action Submittals Required
+type: checkbox
+options:
+ - "Concrete mixture design for each mixture class"
+ - "Required average strength documentation for each mixture"
+ - "Cementitious material certificates of conformance"
+ - "Aggregate gradation and reactivity evaluation"
+ - "Admixture product data and certificates"
+ - "Mixing water qualification for non-potable sources"
+ - "Concrete placement plan"
+ - "Hot-weather concreting plan"
+ - "Cold-weather concreting plan"
+default:
+ - "Concrete mixture design for each mixture class"
+ - "Required average strength documentation for each mixture"
+ - "Cementitious material certificates of conformance"
+ - "Aggregate gradation and reactivity evaluation"
+ - "Admixture product data and certificates"
+ - "Concrete placement plan"
+```
+
+### Concrete shall not be placed in any element until the mixture design for that element has been reviewed and accepted.
+
+### A submittal that omits a required item shall be returned without review, and the review period shall restart on resubmittal.
+
+## Informational Submittals {toc}
+
+### The Contractor shall submit the following before the first structural concrete placement:
+
+- Name, address, and ASTM C1077 qualification documentation for the proposed testing agency, identifying the registered professional engineer providing technical direction
+- Certifications held by each technician who will perform field sampling and testing, with the certifying body and the expiration date for each
+- Batch plant qualification records for every plant that will supply the project
+- Sample delivery ticket demonstrating that each item required by ASTM C94/C94M will be reported
+
+```datasheet
+label: Informational Submittals Required
+type: checkbox
+options:
+ - "Testing agency name and qualification documentation"
+ - "Field testing technician certifications"
+ - "Batch plant qualification records"
+ - "Sample delivery ticket format"
+default:
+ - "Testing agency name and qualification documentation"
+ - "Field testing technician certifications"
+ - "Batch plant qualification records"
+```
+
+## Closeout Submittals {toc}
+
+### The Contractor shall submit the following before concrete work is accepted:
+
+- Complete set of field test reports organized by mixture class and placement date, including compressive strength results, fresh concrete test results, and concrete temperature records
+- Delivery tickets for all concrete incorporated in the work
+- Record of every load rejected, every water addition made at the point of discharge, and every corrective action taken
+- Record of the placement dates, ambient conditions, and protection measures for each element placed under hot-weather or cold-weather provisions
+- Record of every defect reported to the Engineer of Record and the disposition directed for it
+
+```datasheet
+label: Closeout Submittals Required
+type: checkbox
+options:
+ - "Field test reports organized by mixture and date"
+ - "Delivery tickets for concrete incorporated in the work"
+ - "Record of rejected loads and corrective actions"
+ - "Hot-weather and cold-weather placement records"
+ - "Defect reports and directed dispositions"
+default:
+ - "Field test reports organized by mixture and date"
+ - "Delivery tickets for concrete incorporated in the work"
+ - "Record of rejected loads and corrective actions"
+ - "Defect reports and directed dispositions"
+```
+
+# Quality Assurance {toc}
+
+## Concrete Producer and Batch Plant Qualification {toc}
+
+### Concrete shall be furnished by a ready-mixed concrete producer whose plant, equipment, and delivery vehicles conform to ASTM C94/C94M.
+
+### Each supplying plant shall hold a qualification on one of the bases indicated in the datasheet, and the Contractor shall furnish evidence of that qualification before the first delivery.
+
+```datasheet
+label: Acceptable Bases for Batch Plant Qualification
+type: checkbox
+options:
+ - "National Ready Mixed Concrete Association plant certification"
+ - "State department of transportation plant approval"
+ - "Producer quality program audited by an independent agency"
+default:
+ - "National Ready Mixed Concrete Association plant certification"
+ - "State department of transportation plant approval"
+```
+
+### Where more than one plant supplies the project, every plant shall batch from the same accepted mixture design for a given mixture class.
+
+### The delivery ticket shall identify which plant produced the load.
+
+### Supplying a large continuous placement from two plants is ordinary practice and is not itself a defect. The risk it introduces is that the two plants draw from different aggregate stockpiles and different cement silos, so the concrete satisfies the same specification while differing in setting time, finishing window, and color across a single monolithic surface. {note}
+
+## Testing Agency Qualifications {toc}
+
+### The testing agency performing acceptance testing shall conform to ASTM C1077 and shall be under the technical direction of a professional engineer registered in the jurisdiction of the project.
+
+### Field sampling and testing shall be performed by technicians holding current certification for each test method they perform.
+
+### The party indicated in the datasheet shall engage and pay the acceptance testing agency.
+
+```datasheet
+label: Acceptance Testing Agency Engaged By
+type: radio
+options:
+ - "Owner"
+ - "Contractor"
+default: "Owner"
+```
+
+### The testing agency shall transmit each test result to the Engineer of Record and to the Contractor within 24 hours of the test.
+
+### The Contractor shall give the testing agency at least 24 hours notice of each placement, safe access to the point of discharge, and protected space on site for the initial curing of standard-cured specimens.
+
+### Acceptance decisions rest with the Engineer of Record regardless of which party engages the testing agency. The agency reports results; it does not accept or reject work, and its presence transfers no part of the Contractor's responsibility for furnishing conforming concrete. {note}
+
+## Pre-Placement Conference {toc}
+
+### A pre-placement conference shall be held before the first structural concrete placement.
+
+### The conference shall be attended by the Contractor's superintendent, the concrete producer's technical representative, the testing agency's project manager, the finishing subcontractor, and the Engineer of Record.
+
+### The conference agenda shall cover the accepted mixture designs, the placement sequence and joint locations, the consolidation method and equipment, the hot-weather and cold-weather plans, the curing plan required by [[sync/concrete-curing-and-finishing]], the field testing plan, and the procedure for handling a rejected load in the middle of a placement.
+
+## Mixture Qualification {toc}
+
+### The required average compressive strength shall be established for each mixture on a basis indicated in the datasheet, in accordance with ACI 301.
+
+```datasheet
+label: Permitted Basis for Establishing Required Average Strength
+type: checkbox
+options:
+ - "Production strength record with calculated standard deviation"
+ - "Trial mixtures proportioned across a strength range"
+ - "Conservative overdesign without a strength record"
+default:
+ - "Production strength record with calculated standard deviation"
+ - "Trial mixtures proportioned across a strength range"
+```
+
+### Where a production strength record is used, the record shall satisfy the number of tests, the recency, and the similarity-of-materials conditions of ACI 301, and the standard deviation shall be computed in accordance with ACI 214R.
+
+### Where fewer test results are available than the record basis requires, the required average strength shall be increased by the applicable modification factor of ACI 301.
+
+### The Contractor shall proportion each mixture to the required average compressive strength, not to the specified compressive strength.
+
+### The specified compressive strength is a design value: the strength the structure was analyzed for and the floor below which the material is presumed deficient. Production concrete varies from batch to batch, so a mixture proportioned to average exactly the specified strength would fall below it in roughly half of all tests. The required average strength is the target that shifts the whole distribution up far enough that the acceptance criteria are met at the variability the producer can actually demonstrate. {note}
+
+### A production strength record reflects the variability of the producing plant under working conditions, while trial mixtures reflect laboratory batching and curing. Where the two disagree, the record is the closer predictor of what will arrive at the point of discharge. {note}
+
+### Acceptance of a mixture design confirms only that the submitted proportions satisfy this standard. It transfers to the Engineer of Record no responsibility for batching, delivery, placement, or the strength actually produced. {note}
+
+# Exposure Classes and Durability Basis {toc}
+
+## ACI 318 assigns every concrete member four exposure classes — freezing and thawing, sulfate, contact with water, and corrosion protection of reinforcement — and from those classes fixes the maximum water-cementitious materials ratio, the minimum specified compressive strength, the air content, the cementitious materials permitted, and the allowable chloride ion content. The classes are the controlling input to every mixture on the project, not a durability footnote appended to a strength requirement. {note}
+
+## Specifying strength alone is the most common durability defect in structural concrete. A mixture can reach 4000 psi comfortably at a water-cementitious materials ratio of 0.55 and still scale apart in three winters of deicing salt, because resistance to freezing and thawing comes from entrained air and low permeability rather than from strength. {note}
+
+## The Engineer of Record shall assign the exposure classes for each member and shall record them in the datasheet.
+
+```datasheet
+label: Freeze-Thaw Exposure Class
+type: select
+options:
+ - "F0 — not exposed to freezing-and-thawing cycles"
+ - "F1 — exposed to freezing-and-thawing cycles with limited exposure to water"
+ - "F2 — exposed to freezing-and-thawing cycles with frequent exposure to water"
+ - "F3 — exposed to freezing-and-thawing cycles with frequent exposure to water and to deicing chemicals"
+```
+
+```datasheet
+label: Sulfate Exposure Class
+type: select
+options:
+ - "S0 — negligible water-soluble sulfate in soil and in water"
+ - "S1 — moderate sulfate concentration in soil or water, including seawater exposure"
+ - "S2 — severe sulfate concentration in soil or water"
+ - "S3 — very severe sulfate concentration in soil or water"
+```
+
+```datasheet
+label: Contact-with-Water Exposure Class
+type: select
+options:
+ - "W0 — concrete dry in service"
+ - "W1 — concrete in contact with water where low permeability is not required"
+ - "W2 — concrete in contact with water where low permeability is required"
+```
+
+```datasheet
+label: Corrosion-Protection Exposure Class
+type: select
+options:
+ - "C0 — concrete dry or protected from moisture in service"
+ - "C1 — concrete exposed to moisture but not to an external source of chlorides"
+ - "C2 — concrete exposed to moisture and to an external source of chlorides"
+```
+
+## The sulfate exposure class shall be assigned from testing of the site soil and groundwater reported in the geotechnical investigation, using the concentration limits of ACI 318 Table 19.3.1.1.
+
+## Where a member is subject to more than one condition within a category, the more severe class of that category shall be assigned.
+
+## The maximum water-cementitious materials ratio, the minimum specified compressive strength, the cementitious material restrictions, and the maximum water-soluble chloride ion content for each mixture shall satisfy ACI 318 Table 19.3.2.1 for the exposure classes assigned to the members that mixture serves.
+
+## The water-soluble chloride ion content of the hardened concrete shall be determined in accordance with ASTM C1218/C1218M at the age required by ACI 318.
+
+## Assigning a severe exposure class where the condition does not exist is not a cost-free conservatism. An F3 assignment forces entrained air into the mixture, and entrained air in an interior floor slab that will be hard-troweled is a recognized cause of surface blistering and delamination. {note}
+
+# Concrete Mixture Classes {toc}
+
+## A mixture class is a distinct proportioned mixture with its own strength, exposure, and workability requirements, and each class carries its own qualification, submittal, and strength record. Classes multiply for real reasons: a mat foundation and an interior column can share a specified strength while needing different aggregate sizes, different delivery temperatures, and different admixtures. {note}
+
+## The mixture classes required for the project shall be as indicated in the datasheet.
+
+```datasheet
+label: Mixture Classes Required
+type: checkbox
+options:
+ - "Footings, foundations, and grade beams"
+ - "Below-grade walls"
+ - "Slabs on grade"
+ - "Elevated slabs and decks"
+ - "Columns and structural walls above grade"
+ - "Exterior structural concrete exposed to weather"
+ - "Structural lightweight concrete"
+ - "Lean concrete fill and mud mats"
+default: "Footings, foundations, and grade beams"
+```
+
+## The specified compressive strength for each mixture class shall be as indicated in the datasheet.
+
+```datasheet
+label: Specified Compressive Strength — Footings, Foundations, and Grade Beams
+type: range
+unit: psi
+drawing_ref: "concrete mixture schedule on the structural drawings"
+options:
+ min: 2500
+ max: 12000
+ setpoints: [2500, 3000, 3500, 4000, 4500, 5000, 6000, 7000, 8000, 10000, 12000]
+default: deferred
+```
+
+```datasheet
+label: Specified Compressive Strength — Below-Grade Walls
+type: range
+unit: psi
+drawing_ref: "concrete mixture schedule on the structural drawings"
+options:
+ min: 2500
+ max: 12000
+ setpoints: [2500, 3000, 3500, 4000, 4500, 5000, 6000, 7000, 8000, 10000, 12000]
+default: deferred
+```
+
+```datasheet
+label: Specified Compressive Strength — Slabs on Grade
+type: range
+unit: psi
+drawing_ref: "concrete mixture schedule on the structural drawings"
+options:
+ min: 2500
+ max: 8000
+ setpoints: [2500, 3000, 3500, 4000, 4500, 5000, 6000, 8000]
+default: deferred
+```
+
+```datasheet
+label: Specified Compressive Strength — Elevated Slabs and Decks
+type: range
+unit: psi
+drawing_ref: "concrete mixture schedule on the structural drawings"
+options:
+ min: 3000
+ max: 12000
+ setpoints: [3000, 3500, 4000, 4500, 5000, 6000, 7000, 8000, 10000, 12000]
+default: deferred
+```
+
+```datasheet
+label: Specified Compressive Strength — Columns and Structural Walls Above Grade
+type: range
+unit: psi
+drawing_ref: "concrete mixture schedule on the structural drawings"
+options:
+ min: 3000
+ max: 16000
+ setpoints: [3000, 3500, 4000, 4500, 5000, 6000, 7000, 8000, 10000, 12000, 14000, 16000]
+default: deferred
+```
+
+```datasheet
+label: Specified Compressive Strength — Lean Concrete Fill and Mud Mats
+type: range
+unit: psi
+options:
+ min: 500
+ max: 3000
+ setpoints: [500, 1000, 1500, 2000, 2500, 3000]
+default: 2000
+```
+
+## Specified compressive strength is an output of the structural analysis of a member, so it is recorded on the structural drawings rather than chosen when the specification is written. A template that asserts a strength invites a project to accept a number nobody designed for. {note}
+
+## Where the exposure classes assigned to a member require a higher minimum compressive strength than the structural design, the higher value shall govern.
+
+## Each mixture class shall carry a unique designation, and that designation shall appear on the mixture design submittal, on every delivery ticket, and on every test report for that mixture.
+
+## Where a limit on drying shrinkage is indicated in the datasheet, the mixture design submittal shall demonstrate compliance by testing in accordance with ASTM C157/C157M at the drying age stated on the submittal.
+
+```datasheet
+label: Maximum Drying Shrinkage
+type: range
+unit: "%"
+options:
+ min: 0.02
+ max: 0.08
+ setpoints: [0.02, 0.03, 0.035, 0.04, 0.045, 0.05, 0.06, 0.08]
+```
+
+## Where a minimum cementitious materials content is indicated in the datasheet, each mixture shall meet or exceed it.
+
+```datasheet
+label: Minimum Cementitious Materials Content
+type: range
+unit: lb/cy
+options:
+ min: 400
+ max: 800
+ step: 10
+```
+
+## Drying shrinkage is what makes a slab curl at its joints and crack between them, and it is driven mostly by the volume of water and paste in the mixture rather than by its strength. Limiting it is a mixture-level control that competes directly with workability, which is why it is specified where slab performance governs and left unspecified where it does not. {note}
+
+## A minimum cementitious materials content buys finishability: a lean mixture screeds and floats badly and leaves an open, dusting surface. It also works against the shrinkage and heat limits above, so the three constraints are set together or one of them silently loses. {note}
+
+# Maximum Water-Cementitious Materials Ratio {toc}
+
+## The water-cementitious materials ratio is the strongest single control on the permeability of concrete, and permeability governs nearly every durability mechanism that attacks it: chloride ingress to the reinforcement, sulfate attack on the paste, freeze-thaw damage, and the moisture supply that drives alkali-silica reaction. It is also the parameter most easily destroyed on site, because a water addition small enough to look harmless moves the ratio further than most engineers expect. {note}
+
+## The maximum water-cementitious materials ratio for each mixture shall be the lesser of the value indicated in the datasheet and the value required by ACI 318 Table 19.3.2.1 for the exposure classes assigned to that mixture.
+
+```datasheet
+label: Maximum Water-Cementitious Materials Ratio
+type: range
+options:
+ min: 0.32
+ max: 0.65
+ setpoints: [0.32, 0.36, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.55, 0.6, 0.65]
+```
+
+## Free water contributed by aggregate moisture, by ice batched as part of the mixing water, by liquid admixtures, and by any water added at the point of discharge shall be included in the calculation of the water-cementitious materials ratio.
+
+## Mixtures proportioned below a water-cementitious materials ratio of roughly 0.40 produce very little bleed water. The finishing window shortens, and early curing stops being good practice and becomes the difference between a sound surface and a plastic-cracked one. {note}
+
+# Cementitious Materials {toc}
+
+## Hydraulic Cement {toc}
+
+### Hydraulic cement shall be limited to the types indicated in the datasheet, and each shall conform to the specification under which its type is designated.
+
+```datasheet
+label: Permitted Hydraulic Cement Types
+type: checkbox
+options:
+ - "Portland cement Type I under ASTM C150/C150M"
+ - "Portland cement Type II under ASTM C150/C150M"
+ - "Portland cement dual-certified as Type I and Type II under ASTM C150/C150M"
+ - "Portland cement Type III under ASTM C150/C150M"
+ - "Portland cement Type V under ASTM C150/C150M"
+ - "Portland-limestone cement Type IL under ASTM C595/C595M"
+ - "Portland-slag cement Type IS under ASTM C595/C595M"
+ - "Portland-pozzolan cement Type IP under ASTM C595/C595M"
+ - "Ternary blended cement Type IT under ASTM C595/C595M"
+ - "Hydraulic cement under the performance requirements of ASTM C1157/C1157M"
+default:
+ - "Portland cement Type II under ASTM C150/C150M"
+ - "Portland cement dual-certified as Type I and Type II under ASTM C150/C150M"
+ - "Portland-limestone cement Type IL under ASTM C595/C595M"
+```
+
+### Cementitious materials for sulfate exposure classes S1, S2, and S3 shall satisfy the cement type and supplementary cementitious material requirements of ACI 318 Table 19.3.2.1 for the assigned class.
+
+### Where a cement of high early strength is used, the mixture design submittal shall state the resulting increase in early heat of hydration, and the Contractor shall include the corresponding thermal-control measures in the placement plan.
+
+### A single cement source and type shall be used for all concrete of a given mixture class unless a change is accepted in writing by the Engineer of Record.
+
+### High-early-strength cement reaches a given strength sooner because it is ground finer and hydrates faster, and the same reaction releases its heat sooner. In a thin section placed in cold weather that is an advantage; in a thick element, or in warm weather, it raises the peak temperature, shortens the finishing window, and increases the risk of thermal cracking. {note}
+
+### Portland-limestone cement replaces part of the clinker with finely ground limestone and is produced and specified as a cement rather than as a supplementary cementitious material. A mixture using it is not thereby a blended mixture, and the supplementary cementitious material limits below apply only to what is added at the batch plant. {note}
+
+## Supplementary Cementitious Materials {toc}
+
+### Supplementary cementitious materials shall be limited to the materials indicated in the datasheet.
+
+```datasheet
+label: Permitted Supplementary Cementitious Materials
+type: checkbox
+options:
+ - "Class F fly ash under ASTM C618"
+ - "Class C fly ash under ASTM C618"
+ - "Natural pozzolan under ASTM C618"
+ - "Slag cement under ASTM C989/C989M"
+ - "Silica fume under ASTM C1240"
+ - "Ground-glass pozzolan under ASTM C1866/C1866M"
+ - "No supplementary cementitious materials permitted"
+default:
+ - "Class F fly ash under ASTM C618"
+ - "Slag cement under ASTM C989/C989M"
+```
+
+### The maximum content of each supplementary cementitious material, and of all of them combined, shall be as indicated in the datasheet, expressed as a percentage by mass of the total cementitious materials.
+
+```datasheet
+label: Maximum Fly Ash Content
+type: range
+unit: "%"
+options:
+ min: 0
+ max: 50
+ step: 5
+```
+
+```datasheet
+label: Maximum Slag Cement Content
+type: range
+unit: "%"
+options:
+ min: 0
+ max: 80
+ step: 5
+```
+
+```datasheet
+label: Maximum Silica Fume Content
+type: range
+unit: "%"
+options:
+ min: 0
+ max: 15
+ step: 1
+```
+
+```datasheet
+label: Maximum Total Supplementary Cementitious Material Content
+type: range
+unit: "%"
+options:
+ min: 0
+ max: 80
+ step: 5
+```
+
+### Where concrete is assigned to exposure class F3, the content of each supplementary cementitious material and the total of all of them shall not exceed the limits of ACI 318 for that class.
+
+### The mixture design submittal shall state the age at which each mixture containing supplementary cementitious materials attains its specified compressive strength.
+
+### Supplementary cementitious materials react with the calcium hydroxide released by cement hydration rather than with water directly, so they build strength later and, in exchange, produce a denser and markedly less permeable paste. The practical consequences are a slower early strength gain that shifts formwork and loading schedules, a longer curing period, and substantially better long-term performance wherever chloride or sulfate ingress is the governing durability demand. {note}
+
+### Silica fume has a surface area roughly two orders of magnitude greater than portland cement. That is why it reduces permeability so sharply at low replacement rates, and also why a silica fume mixture bleeds almost nothing and will crack in the plastic state if the surface is left unprotected between screeding and curing. {note}
+
+# Aggregates {toc}
+
+## Aggregate Type and Size {toc}
+
+### Aggregate for each mixture class shall be of the density class indicated in the datasheet.
+
+```datasheet
+label: Aggregate Density Class
+type: select
+options:
+ - "Normalweight aggregate conforming to ASTM C33/C33M"
+ - "Structural lightweight aggregate conforming to ASTM C330/C330M"
+ - "Sand-lightweight combination of normalweight fine and lightweight coarse aggregate"
+default: "Normalweight aggregate conforming to ASTM C33/C33M"
+```
+
+### The nominal maximum size of coarse aggregate shall be as indicated in the datasheet.
+
+```datasheet
+label: Nominal Maximum Coarse Aggregate Size
+type: range
+unit: in
+options:
+ min: 0.375
+ max: 2
+ setpoints: [0.375, 0.5, 0.75, 1, 1.5, 2]
+default: 0.75
+```
+
+### The nominal maximum aggregate size shall not exceed one-fifth of the narrowest dimension between form faces, one-third of the depth of a slab, or three-quarters of the minimum clear spacing between individual reinforcing bars, bundles of bars, or tendons, whichever of these is least.
+
+### Where the nominal maximum size indicated in the datasheet exceeds any of those limits at a specific member, the Contractor shall notify the Engineer of Record before placement, and the Engineer of Record shall direct either a smaller aggregate for that member or a revision to the member.
+
+### Coarse and fine aggregate for normalweight concrete shall conform to ASTM C33/C33M.
+
+### Fine aggregate shall have a fineness modulus between 2.3 and 3.1, and the fineness modulus of the aggregate supplied shall not vary from the value used in the mixture design by more than 0.20.
+
+### Aggregate from more than one source shall not be combined within a single mixture class unless that combination was used in the trial mixtures or the strength record that qualified the mixture.
+
+### Larger aggregate reduces the paste volume needed for a given workability, which lowers water demand, drying shrinkage, and cost. Smaller aggregate travels through congested reinforcement and into thin sections that larger stone bridges across. The governing constraint is almost always the bar spacing at the most congested member in the class rather than at the average member. {note}
+
+### The equilibrium density of structural lightweight concrete shall be as indicated in the datasheet.
+
+```datasheet
+label: Equilibrium Density — Structural Lightweight Concrete
+type: range
+unit: pcf
+drawing_ref: "concrete mixture schedule on the structural drawings"
+options:
+ min: 90
+ max: 125
+ setpoints: [90, 95, 100, 105, 110, 115, 120, 125]
+default: deferred
+```
+
+### Lightweight aggregate shall be pre-wetted before batching to the moisture condition assumed in the mixture design.
+
+### Lightweight aggregate is porous, and dry aggregate keeps absorbing mixing water after batching. A load then leaves the plant at its design slump and arrives stiff, which is the single most common reason lightweight concrete draws a request for a water addition it does not actually need. Pre-wetting removes the mechanism. {note}
+
+## Alkali-Aggregate Reactivity {toc}
+
+### Each aggregate source shall be evaluated for alkali-silica and alkali-carbonate reactivity in accordance with ASTM C1778 before the mixture design is submitted.
+
+### The basis on which reactivity is addressed for each aggregate source shall be as indicated in the datasheet.
+
+```datasheet
+label: Alkali-Aggregate Reactivity Basis
+type: select
+options:
+ - "Documented field service record of the aggregate source in comparable exposure"
+ - "Expansion testing of the aggregate under ASTM C1260 or ASTM C1293"
+ - "Expansion testing of the aggregate and cementitious combination under ASTM C1567"
+ - "Prescriptive mitigation by supplementary cementitious materials without expansion testing"
+ - "Prescriptive mitigation by limiting the alkali content of the cementitious materials"
+ - "Chemical mitigation by lithium-bearing admixture"
+```
+
+### An aggregate that exceeds the expansion limits of ASTM C1778 for the project exposure shall not be used unless the mixture incorporates a mitigation shown effective for that aggregate by ASTM C1567 testing or by an equivalent documented service record.
+
+### Alkali-silica reaction is slow, self-propagating, and effectively unrepairable. Reactive silica in the aggregate forms a gel that swells as it takes up water, cracking the concrete from the inside over years to decades. No test performed on the fresh concrete detects it, so the only available control is qualification of the aggregate and of the cementitious combination before the first placement. {note}
+
+# Mixing Water {toc}
+
+## Mixing water shall be potable, or shall conform to ASTM C1602/C1602M.
+
+## Wash water and water reclaimed from concrete production operations may be used only where the producer demonstrates conformance to ASTM C1602/C1602M and reports the solids content of the reclaimed water on the mixture design submittal.
+
+## Water shall not be used as mixing water in concrete containing reinforcement or other embedded metal where its chloride ion content would cause the concrete to exceed the water-soluble chloride ion limit required for the assigned corrosion-protection exposure class.
+
+## Ice used to reduce the temperature of the concrete shall be batched as part of the mixing water and shall be completely melted before discharge.
+
+## Water is the only constituent of concrete that is commonly available on site in unlimited quantity and at no cost, which is exactly why its control is written into so many separate requirements: the mixture design, the batching record, the delivery ticket, and the discharge policy each constrain the same quantity from a different direction. {note}
+
+# Chemical Admixtures {toc}
+
+## Chemical admixtures shall be limited to the types indicated in the datasheet.
+
+```datasheet
+label: Permitted Chemical Admixture Types
+type: checkbox
+options:
+ - "Air-entraining admixture under ASTM C260/C260M"
+ - "Type A water-reducing admixture under ASTM C494/C494M"
+ - "Type B retarding admixture under ASTM C494/C494M"
+ - "Type C accelerating admixture under ASTM C494/C494M"
+ - "Type D water-reducing and retarding admixture under ASTM C494/C494M"
+ - "Type E water-reducing and accelerating admixture under ASTM C494/C494M"
+ - "Type F high-range water-reducing admixture under ASTM C494/C494M"
+ - "Type G high-range water-reducing and retarding admixture under ASTM C494/C494M"
+ - "Type S specific-performance admixture under ASTM C494/C494M"
+ - "Admixture for flowing concrete under ASTM C1017/C1017M"
+ - "Viscosity-modifying admixture"
+ - "Shrinkage-reducing admixture"
+ - "Corrosion-inhibiting admixture"
+ - "Chloride-bearing accelerating admixture"
+default:
+ - "Air-entraining admixture under ASTM C260/C260M"
+ - "Type A water-reducing admixture under ASTM C494/C494M"
+ - "Type D water-reducing and retarding admixture under ASTM C494/C494M"
+ - "Type F high-range water-reducing admixture under ASTM C494/C494M"
+```
+
+## The producer shall certify each admixture as compatible with the cement, the supplementary cementitious materials, the other admixtures, and the aggregate of the mixture in which it is used.
+
+## Admixture dosages shall remain within the range used to qualify the mixture, and a dosage outside that range shall require a revised mixture design submittal.
+
+## Admixtures containing intentionally added chlorides shall not be used in prestressed concrete, in concrete containing aluminum embedments, or in concrete in contact with galvanized steel.
+
+## Unless chloride-bearing accelerating admixtures are permitted in the datasheet, accelerating admixtures shall be non-chloride formulations.
+
+## Where chloride-bearing accelerating admixtures are permitted, the mixture design submittal shall demonstrate that the total water-soluble chloride ion content of the concrete remains within the limit required for the assigned corrosion-protection exposure class.
+
+## A water reducer lets a mixture reach its target slump at less water, which lowers the water-cementitious materials ratio without changing the cement content. That is the mechanism by which most durability requirements are met economically, and it is why a load that arrives stiff is corrected at the plant by dosage rather than on site by water. {note}
+
+## Retarders extend the time to initial set, which is what keeps successive lifts knitting together in hot weather or over a long haul. Accelerators shorten it, which is what allows finishing to start at a workable hour in cold weather. Both shift the finishing window rather than the final strength, and both interact with supplementary cementitious materials, so dosage is established by trial rather than from a catalog. {note}
+
+# Fresh Concrete Properties {toc}
+
+## Air Content {toc}
+
+### Air-entraining admixture shall conform to ASTM C260/C260M.
+
+### The total air content of concrete assigned to exposure class F1, F2, or F3 shall be as required by ACI 318 Table 19.3.3.1 for the assigned class and the nominal maximum aggregate size of the mixture.
+
+### The air content tolerance at the point of discharge shall be as specified in ASTM C94/C94M.
+
+### Each mixture shall be proportioned to reach its specified compressive strength at the required air content, and the strength loss caused by entrained air shall be offset within the mixture design rather than by reducing air on site.
+
+### Where a mixture is assigned exposure class F0 and serves an interior floor slab that will receive a hard-troweled finish, air-entraining admixture shall not be used in that mixture.
+
+### Entrained air is a system of very small, closely spaced voids distributed through the paste. When pore water freezes and expands, the voids give it somewhere to go; without them the expansion works against the paste and each cycle removes a little more of the surface. Entrapped air from poor consolidation does nothing of the kind, because those voids are too large and too widely separated to relieve the pressure. {note}
+
+### Each percentage point of total air costs roughly three to five percent of compressive strength, which is how an air content run high for workability quietly erodes the strength margin the mixture was proportioned for. {note}
+
+### Air deliberately entrained in a slab that is then hard-troweled can be sealed beneath the densified surface and lift it away as a blister or a delamination, because the finishing operation closes the surface before that air has escaped. {note}
+
+## Slump and Slump Flow {toc}
+
+### The specified slump for each conventional mixture shall be as indicated in the datasheet, measured in accordance with ASTM C143/C143M at the point of discharge.
+
+```datasheet
+label: Specified Slump — Conventional Mixtures
+type: range
+unit: in
+options:
+ min: 1
+ max: 10
+ step: 0.5
+```
+
+### The slump tolerance shall be as specified in ASTM C94/C94M.
+
+### Each mixture shall be proportioned to deliver its specified slump at the point of discharge under the haul time and ambient conditions anticipated for the placements it serves.
+
+### Whether self-consolidating concrete may be used shall be as indicated in the datasheet.
+
+```datasheet
+label: Self-Consolidating Concrete
+type: radio
+options:
+ - "Permitted for any structural element"
+ - "Permitted for elements the Engineer of Record accepts in writing"
+ - "Not permitted"
+```
+
+### Where self-consolidating concrete is used, its slump flow shall be as indicated in the datasheet, measured in accordance with ASTM C1611/C1611M.
+
+```datasheet
+label: Slump Flow — Self-Consolidating Concrete
+type: range
+unit: in
+options:
+ min: 18
+ max: 32
+ step: 1
+```
+
+### Where self-consolidating concrete is used, static segregation shall be verified in accordance with ASTM C1610/C1610M and passing ability shall be verified in accordance with ASTM C1621/C1621M as part of mixture qualification.
+
+### Slump measures the workability of a conventional mixture, and only indirectly: it responds to water content, admixture dosage, aggregate gradation, temperature, and elapsed time since batching all at once. Its value on site is as a consistency check, because a load arriving well outside the qualified slump is a load whose proportions are not what was accepted, whatever the cause. {note}
+
+### Self-consolidating concrete fills and de-airs without vibration, using a high-range water reducer together with a viscosity-modifying admixture to make a mixture that flows and levels under its own weight while holding its coarse aggregate in suspension. It is measured by slump flow rather than slump, it exerts full hydrostatic pressure on the formwork, and it is unforgiving of a segregating mixture, so adopting it changes the formwork design and the quality control regime rather than only the placement method. {note}
+
+## Concrete Temperature at Delivery {toc}
+
+### Concrete temperature shall be measured in accordance with ASTM C1064/C1064M at the point of discharge and shall be recorded with every strength test sample.
+
+### The maximum concrete temperature at the point of discharge shall be as indicated in the datasheet.
+
+```datasheet
+label: Maximum Concrete Temperature at Discharge
+type: range
+unit: "°F"
+options:
+ min: 70
+ max: 95
+ setpoints: [70, 75, 80, 85, 90, 95]
+default: 90
+```
+
+### The minimum concrete temperature at placement shall be as required by ACI 306R for the least dimension of the section being placed.
+
+### Concrete temperature drives the rate of hydration, so it sets the finishing window at one end and the rate of strength gain at the other. A high delivery temperature costs water demand, slump retention, and ultimate strength, and it raises the peak temperature the element will reach. A low delivery temperature slows setting until finishing runs into the night and, below freezing, stops hydration outright. {note}
+
+# Batching, Mixing, and Delivery {toc}
+
+## Concrete shall be batched, mixed, and delivered in accordance with ASTM C94/C94M.
+
+## Each load shall be accompanied by a delivery ticket reporting every item required by ASTM C94/C94M together with the mixture class designation, the batch plant, the batch time, and the quantity of water withheld at the plant.
+
+## The maximum elapsed time from the introduction of mixing water to the completion of discharge shall be as indicated in the datasheet.
+
+```datasheet
+label: Maximum Elapsed Time from Batching to Completion of Discharge
+type: range
+unit: min
+options:
+ min: 45
+ max: 120
+ setpoints: [45, 60, 75, 90, 105, 120]
+default: 90
+```
+
+## Discharge shall be completed before the drum has revolved 300 times at mixing and agitating speed following the introduction of mixing water.
+
+## The field water addition policy for the project shall be as indicated in the datasheet.
+
+```datasheet
+label: Field Water Addition Policy
+type: radio
+options:
+ - "One addition permitted at the point of discharge within the water withheld from the accepted mixture"
+ - "No water addition permitted after the load leaves the batch plant"
+default: "One addition permitted at the point of discharge within the water withheld from the accepted mixture"
+```
+
+## Where a water addition is permitted, it shall be made in a single increment before any part of the load has been discharged.
+
+## A water addition shall not cause the mixture to exceed the maximum water-cementitious materials ratio required for its exposure classes.
+
+## Concrete to which water has been added shall be mixed at mixing speed for at least 30 revolutions before discharge resumes.
+
+## Every water addition shall be recorded on the delivery ticket with the quantity added and the name of the person who authorized it.
+
+## Water shall be added only on the authorization of the Contractor's superintendent, who shall verify the remaining withheld water on the delivery ticket before authorizing it.
+
+## A load to which water was added outside the field water addition policy shall be rejected and shall not be placed in the work.
+
+## The cost of a rejected load, of its disposal, and of any delay it causes shall be borne by the Contractor, except where the rejection is caused by an act of the Owner or by a change directed in writing.
+
+## The water withheld at the plant is not spare water. It is the difference between the mixture's design water and the water actually batched, held back so the load can be brought to its design slump at the site instead of arriving over-wet. Water added beyond it raises the water-cementitious materials ratio, and the loss of strength and durability that follows is permanent and invisible until a cylinder breaks low or the surface scales years later. {note}
+
+# Placement and Consolidation {toc}
+
+## Pre-Placement Verification {toc}
+
+### Concrete shall not be placed in any element until formwork for that element has been inspected and released in accordance with [[sync/concrete-formwork]].
+
+### Concrete shall not be placed in any element until reinforcement placement, support, and cover for that element have been verified in accordance with [[sync/concrete-reinforcement]].
+
+### Concrete shall not be placed in any element until embedded items, sleeves, anchor rods, and waterstops have been set and secured in accordance with [[sync/concrete-accessories]] and [[sync/concrete-joints-and-waterstops]].
+
+### Debris, standing water, ice, snow, and loose material shall be removed from the interior of the forms and from the placement surface immediately before concrete is placed.
+
+### The subgrade or supporting surface beneath a slab on grade shall be in the moisture condition required by [[sync/slab-on-grade]] at the time of placement.
+
+### Concrete shall not be placed until the testing agency technician is present at the point of discharge.
+
+### The Contractor's superintendent shall record the completion of each pre-placement verification, and the record shall be available to the Engineer of Record before placement begins.
+
+## Depositing Concrete {toc}
+
+### Each mixture shall be proportioned for the placement methods indicated in the datasheet.
+
+```datasheet
+label: Placement Methods the Mixtures Must Accommodate
+type: checkbox
+options:
+ - "Boom or line concrete pump"
+ - "Crane and bucket"
+ - "Direct chute from the truck"
+ - "Belt conveyor"
+ - "Concrete buggy or motorized cart"
+ - "Tremie placement under water"
+default:
+ - "Boom or line concrete pump"
+ - "Direct chute from the truck"
+```
+
+### Concrete shall be deposited as near as practicable to its final position.
+
+### Concrete shall not be moved laterally into position by vibration.
+
+### The maximum free fall of concrete without a drop chute, tremie, or elephant trunk shall be as indicated in the datasheet.
+
+```datasheet
+label: Maximum Free Fall Without a Drop Chute
+type: range
+unit: ft
+options:
+ min: 3
+ max: 15
+ setpoints: [3, 4, 5, 6, 8, 10, 15]
+default: 5
+```
+
+### Concrete shall not be permitted to fall against reinforcement, form faces, or embedded items in a manner that separates the coarse aggregate from the mortar.
+
+### Pump lines shall be primed with mortar or a proprietary priming material, and the priming material shall be discharged outside the work rather than into a structural element.
+
+### Water used to clean pump lines, buckets, or chutes shall be discharged outside the forms.
+
+### Free fall by itself is not what causes segregation, because a vertical drop into open air lands as a coherent stream. Segregation happens when the stream strikes something on the way down, so the height that matters is the height above the last obstruction. A congested column cage makes a 4 ft drop worse than a 12 ft drop into an empty form. {note}
+
+## Lift Depth and Placement Rate {toc}
+
+### The maximum depth of a single lift in walls and columns shall be as indicated in the datasheet.
+
+```datasheet
+label: Maximum Lift Depth — Walls and Columns
+type: range
+unit: in
+options:
+ min: 12
+ max: 36
+ setpoints: [12, 18, 24, 30, 36]
+default: 18
+```
+
+### The rate of placement in vertical elements shall not exceed the rate assumed in the formwork design accepted under [[sync/concrete-formwork]].
+
+### Each lift shall be placed and consolidated before the lift beneath it has reached initial set.
+
+### The vibrator shall penetrate the full depth of the lift being placed and shall extend approximately 6 in. into the lift beneath it.
+
+### Lift depth is governed from two directions at once. It cannot exceed the reach over which the vibrator can genuinely consolidate, and the rate at which lifts are stacked cannot exceed the lateral pressure the formwork was designed for. The two limits are set by different parties and are the pair most often reconciled only after a form blows out. {note}
+
+## Consolidation {toc}
+
+### All concrete other than self-consolidating concrete shall be consolidated by internal mechanical vibration in accordance with ACI 309R.
+
+### The vibrator head shall be sized so that its radius of action covers the section being consolidated at the insertion spacing used.
+
+### Insertion points shall be spaced at not more than 1.5 times the radius of action of the vibrator head, and the insertion pattern shall leave no part of the placement outside the radius of action of an insertion.
+
+### The vibrator shall be inserted vertically and rapidly, held until the surface takes on a uniform sheen and air bubbles stop rising, and withdrawn slowly enough that the concrete closes behind it.
+
+### The vibrator shall not be dragged horizontally through the concrete and shall not be used as a rodding tool.
+
+### The vibrator shall not be held in sustained contact with reinforcement, embedded items, or form faces.
+
+### Re-vibration of a lift is permitted while the vibrator still sinks into the concrete under its own weight, and shall not be performed after initial set.
+
+### Consolidation is the operation that converts a placed mixture into the material the design assumed. Entrapped air occupies roughly 5 to 20 percent of the volume of freshly placed concrete, and every part of it left behind is lost strength, lost bond to the reinforcement, and a path for water. Honeycombing, sand streaking, and surface voids are the same defect seen from outside. {note}
+
+### Re-vibration within the plastic period closes the settlement cracks and voids that form as concrete bleeds and subsides around reinforcement, particularly over the top bars of deep members, and it does not reduce strength while the concrete still responds to the vibrator. {note}
+
+### Self-consolidating concrete is designed to fill and de-air without vibration, so vibrating it can drive the coarse aggregate down through the paste and produce exactly the segregation the mixture was formulated to avoid. {note}
+
+## Continuity of Placement {toc}
+
+### Concrete shall be placed continuously within each element or between the joints shown on the joint layout accepted under [[sync/concrete-joints-and-waterstops]].
+
+### The Contractor shall establish the placement rate, the number of trucks, and the discharge sequence needed to cover each layer before the layer beneath it reaches initial set, accounting for haul time, ambient conditions, and admixture dosage.
+
+### Where placement is interrupted for a period that puts the preceding layer at risk of initial set, the Contractor shall immediately notify the Engineer of Record.
+
+### Where the parties disagree whether an interruption has produced a cold joint, the Engineer of Record shall make the initial determination and shall direct either that placement resume, that the interruption be treated as a construction joint prepared in accordance with [[sync/concrete-joints-and-waterstops]], or that the element be evaluated as defective work.
+
+### A cold joint is the plane left where a layer of concrete reached initial set before the next layer was placed against it. It differs from a construction joint only in that it was not planned, not located where the design can tolerate it, and not prepared, so it carries reduced shear transfer and, below grade, a leakage path. {note}
+
+# Hot and Cold Weather Concreting {toc}
+
+## Hot Weather Placement {toc}
+
+### Hot weather concreting measures shall be implemented whenever the concrete temperature at discharge would otherwise exceed the maximum indicated in the datasheet, or whenever the calculated rate of evaporation from the concrete surface would exceed the threshold indicated in the datasheet.
+
+```datasheet
+label: Evaporation Rate Threshold Requiring Protective Measures
+type: range
+unit: "lb/ft²/hr"
+options:
+ min: 0.05
+ max: 0.3
+ setpoints: [0.05, 0.1, 0.15, 0.2, 0.25, 0.3]
+default: 0.2
+```
+
+### The rate of evaporation shall be calculated from the concrete temperature, the ambient temperature, the relative humidity, and the wind speed in accordance with ACI 305R.
+
+### The hot weather measures available on the project shall be as indicated in the datasheet.
+
+```datasheet
+label: Hot Weather Concreting Measures
+type: checkbox
+options:
+ - "Substitution of ice for part of the batch water"
+ - "Sprinkling or shading of coarse aggregate stockpiles"
+ - "Liquid nitrogen cooling of the mixed concrete"
+ - "Reduced haul time and reduced load size"
+ - "Retarding admixture dosed for the anticipated haul and placement time"
+ - "Placement during the cooler hours of the day"
+ - "Wind screens at the perimeter of the placement"
+ - "Fog misting above the placement surface"
+ - "Evaporation retardant applied between screeding and finishing"
+ - "Sunshades over the placement area"
+```
+
+### Where the measures indicated in the datasheet are insufficient to hold the concrete at or below its maximum discharge temperature, placement shall not proceed until additional measures are agreed with the Engineer of Record.
+
+### Plastic shrinkage cracking occurs when water evaporates from the surface of fresh concrete faster than bleed water rises to replace it. The surface goes into tension at a moment when the concrete has almost no tensile strength, and it tears. The cracks run roughly parallel, extend a substantial fraction of the depth, do not close on their own, and cannot be troweled out once the concrete has stiffened. {note}
+
+### Low-bleed mixtures reach the evaporation threshold under conditions that would be harmless for a conventional mixture, because there is less bleed water available to replace what evaporates. A low water-cementitious materials ratio, silica fume, and a high fines content all produce that condition. {note}
+
+## Cold Weather Placement {toc}
+
+### Cold weather concreting measures shall be implemented when the ambient temperature is at or below 40°F, or is forecast to fall below 40°F at any time during the protection period, in accordance with ACI 306R.
+
+### The cold weather measures available on the project shall be as indicated in the datasheet.
+
+```datasheet
+label: Cold Weather Concreting Measures
+type: checkbox
+options:
+ - "Heated mixing water"
+ - "Heated aggregate"
+ - "Non-chloride accelerating admixture"
+ - "Insulating blankets over concrete and forms"
+ - "Insulated formwork left in place through the protection period"
+ - "Heated enclosure with vented combustion heaters"
+ - "Heated enclosure with electric or indirect-fired heaters"
+ - "Ground thawing before placement on grade"
+```
+
+### Concrete shall not be placed on or against frozen subgrade, frozen formwork, frozen reinforcement, ice, or snow.
+
+### Fresh concrete shall be protected from freezing until it has attained at least the compressive strength indicated in the datasheet, verified by field-cured specimens or by the maturity method.
+
+```datasheet
+label: Minimum Compressive Strength Before Exposure to Freezing
+type: range
+unit: psi
+options:
+ min: 500
+ max: 4000
+ setpoints: [500, 1000, 1500, 2000, 2500, 3000, 3500, 4000]
+default: 500
+```
+
+### The concrete temperature shall be maintained at or above the minimum required by ACI 306R for the least dimension of the section throughout the protection period.
+
+### The rate at which the concrete surface is allowed to cool at the end of the protection period shall not exceed the limit given by ACI 306R for the least dimension of the section.
+
+### The Contractor shall record the concrete surface temperature and the ambient temperature at intervals not exceeding 12 hours throughout the protection period and shall make the record available to the Engineer of Record on request.
+
+### Where a combustion heater is operated inside an enclosure, its exhaust shall be vented to the exterior of the enclosure, and the Contractor shall monitor the carbon monoxide concentration inside the enclosure throughout heater operation.
+
+### Where a combustion heater exhausts into an enclosure, the carbon dioxide in that exhaust reacts with the fresh concrete surface to form a soft, chalky, dusting layer, and the same exhaust accumulates carbon monoxide to concentrations lethal to the crew working inside. Venting the exhaust to the exterior removes both mechanisms at once. {note}
+
+### Concrete that freezes before it reaches roughly 500 psi is permanently damaged. The mixing water expands as it freezes and disrupts the paste structure while that structure is still forming, and warming the element afterward does not restore what was broken. {note}
+
+### Below about 50°F, hydration slows sharply, so a mixture that would be ready to finish at noon in summer is often not ready until the middle of the night. That schedule effect, rather than the risk of freezing, is what most often drives the choice between an accelerator and a heated enclosure. {note}
+
+# Thermal Control of Thick Sections {toc}
+
+## A thick element generates heat faster than it can shed it. Cement hydration is exothermic, the interior is insulated by the concrete around it, and the core of a mat foundation can run far above the temperature at which it was placed while the surface tracks the weather. Two distinct problems follow: the core gets hot enough to damage its own paste chemistry, and the difference between core and surface puts the cooler outer concrete into tension against a restrained interior. {note}
+
+## The least dimension above which a placement is subject to thermal control shall be as indicated in the datasheet.
+
+```datasheet
+label: Least Dimension Above Which Thermal Control Applies
+type: range
+unit: ft
+options:
+ min: 1.5
+ max: 8
+ setpoints: [1.5, 2, 3, 4, 5, 6, 8]
+```
+
+## The Contractor shall submit a thermal control plan for every placement subject to thermal control, identifying the predicted temperature history, the sensor locations, the insulation or cooling measures, and the criterion for ending temperature monitoring.
+
+## The maximum in-place concrete temperature and the maximum difference between the core temperature and the surface temperature shall be as indicated in the datasheet.
+
+```datasheet
+label: Maximum In-Place Concrete Temperature
+type: range
+unit: "°F"
+options:
+ min: 140
+ max: 180
+ setpoints: [140, 150, 158, 160, 170, 180]
+default: 160
+```
+
+```datasheet
+label: Maximum Temperature Difference Between Core and Surface
+type: range
+unit: "°F"
+options:
+ min: 20
+ max: 50
+ setpoints: [20, 25, 30, 35, 40, 45, 50]
+default: 35
+```
+
+## Concrete temperature shall be monitored at the predicted hottest point of the element, at a point within 2 in. of the nearest exposed surface, and at the ambient air, and shall be recorded at intervals not exceeding 2 hours until the maximum temperature difference has passed and is falling.
+
+## Where a monitored temperature exceeds either limit, the Contractor shall immediately notify the Engineer of Record, who shall make the initial determination whether the affected concrete is acceptable, requires evaluation, or requires replacement.
+
+## Insulation removed from a thick element at the end of the monitoring period shall be removed in stages where necessary to keep the surface cooling rate within the limit of ACI 306R for the least dimension of the section.
+
+## Peak core temperature is limited because concrete cured above roughly 160°F can form ettringite later, after the paste has hardened, and the expansion that accompanies it cracks the concrete from within years after placement. The core-to-surface difference is limited for an unrelated reason: the outer concrete contracts as it cools while the hot core does not, and beyond about 35°F of difference the resulting tension exceeds what young concrete can carry. {note}
+
+## Supplementary cementitious materials are the primary tool for both limits, because a mixture with a large fraction of slag cement or fly ash releases the same total heat more slowly and reaches a lower peak. Insulation works on the difference rather than the peak, by keeping the surface warm instead of cooling the core. {note}
+
+# Field Testing and Acceptance {toc}
+
+## Sampling and Test Frequency {toc}
+
+### Concrete shall be sampled at the point of discharge in accordance with ASTM C172/C172M.
+
+### The frequency of strength testing by volume placed shall be as indicated in the datasheet, and shall in no case be less frequent than the minimum required by ACI 318 Section 26.12.2.
+
+```datasheet
+label: Strength Test Frequency by Volume Placed
+type: range
+unit: cy
+options:
+ min: 25
+ max: 150
+ setpoints: [25, 50, 75, 100, 125, 150]
+default: 150
+```
+
+### At least one strength test shall be made for each mixture class on each day that class is placed.
+
+### At least one strength test shall be made for each 5000 ft² of slab or wall surface area placed.
+
+### The number of specimens cast for each strength test shall be as indicated in the datasheet.
+
+```datasheet
+label: Specimens Cast per Strength Test
+type: range
+unit: specimens
+options:
+ min: 2
+ max: 8
+ step: 1
+default: 5
+```
+
+### A strength test shall be the average compressive strength of at least two specimens tested at the acceptance age, and the remaining specimens of the set shall be allocated to early-age indication and to reserve.
+
+### Specimens for acceptance shall be made and standard-cured in accordance with ASTM C31/C31M and tested in accordance with ASTM C39/C39M.
+
+### Unbonded caps used in compression testing shall conform to ASTM C1231/C1231M.
+
+### The acceptance test age shall be as indicated in the datasheet.
+
+```datasheet
+label: Acceptance Test Age
+type: range
+unit: days
+options:
+ min: 3
+ max: 90
+ setpoints: [3, 7, 14, 28, 56, 90]
+default: 28
+```
+
+### Where [[sync/concrete-formwork]] requires strength verification before form or shore removal, the testing agency shall cast additional field-cured specimens for that purpose, and those specimens shall not be used for acceptance.
+
+### A strength test is the average of the specimens tested at the acceptance age, not an individual cylinder. A single low cylinder is ordinary scatter, and the acceptance criteria are written against the test average precisely so that specimen-handling variability does not condemn conforming concrete. {note}
+
+### Where a mixture develops much of its strength after 28 days, as mixtures with a high proportion of slag cement or fly ash do, an acceptance age later than 28 days measures what the structure will actually have and avoids rejecting concrete that is merely slow. The age has to be chosen before the first placement, because the structural schedule depends on it. {note}
+
+## Fresh Concrete Testing {toc}
+
+### At each sampling made for strength testing, the testing agency shall perform and record the tests indicated in the datasheet:
+
+- Temperature of the freshly mixed concrete in accordance with ASTM C1064/C1064M
+- Slump in accordance with ASTM C143/C143M, or slump flow in accordance with ASTM C1611/C1611M for self-consolidating concrete
+- Air content in accordance with ASTM C231/C231M for normalweight concrete, or ASTM C173/C173M for lightweight and other highly porous aggregate concrete
+- Density and yield in accordance with ASTM C138/C138M
+- Batch time, arrival time, and discharge time taken from the delivery ticket
+
+```datasheet
+label: Fresh Concrete Tests Required at Each Sampling
+type: checkbox
+options:
+ - "Temperature of the freshly mixed concrete"
+ - "Slump or slump flow at the point of discharge"
+ - "Air content by the pressure method"
+ - "Air content by the volumetric method"
+ - "Density and yield of the fresh concrete"
+ - "Batch and discharge times from the delivery ticket"
+default:
+ - "Temperature of the freshly mixed concrete"
+ - "Slump or slump flow at the point of discharge"
+ - "Air content by the pressure method"
+ - "Density and yield of the fresh concrete"
+ - "Batch and discharge times from the delivery ticket"
+```
+
+### The pressure method for air content is invalid on lightweight and other highly porous aggregate, because the pressure applied in the test compresses air held inside the aggregate pores and the meter reads that as entrained air. The volumetric method is the one that gives a true reading on those mixtures. {note}
+
+## Rejection of Fresh Concrete {toc}
+
+### A load shall be rejected at the point of discharge, and no part of it placed in the work, where any of the following conditions exists:
+
+- The slump or slump flow lies outside the specified value by more than the tolerance of ASTM C94/C94M
+- The air content lies outside the required value by more than the tolerance of ASTM C94/C94M
+- The concrete temperature is above the maximum or below the minimum required for the placement
+- The elapsed time or the drum revolutions exceed the limits of this standard
+- Water was added outside the field water addition policy
+- The delivery ticket does not identify the load as the accepted mixture class for the element being placed
+
+### The testing agency shall notify the Contractor and the Engineer of Record immediately when a rejection condition is identified.
+
+### The Contractor shall provide a replacement load without interrupting the placement.
+
+## Acceptance of Hardened Concrete {toc}
+
+### The strength of a mixture class shall be accepted when both of the following conditions of ACI 318 Section 26.12.3 are satisfied:
+
+1. Every arithmetic average of any three consecutive strength tests equals or exceeds the specified compressive strength.
+2. No individual strength test falls below the specified compressive strength by more than 500 psi where that strength is 5000 psi or less, or by more than ten percent of it where it exceeds 5000 psi.
+
+### Where a strength test falls below the specified compressive strength, the Contractor shall within 48 hours review and report to the Engineer of Record the batching records, the delivery tickets, the fresh concrete test results, and the curing history for the concrete that test represents.
+
+### Where a strength test fails either acceptance condition, the Engineer of Record shall direct the steps required by ACI 318 Section 26.12.4 to establish the adequacy of the concrete in the affected area.
+
+### Cores taken to evaluate a low strength test shall be obtained and tested in accordance with ASTM C42/C42M.
+
+### Concrete in the area represented by cores shall be accepted as structurally adequate where the average compressive strength of three cores is at least 85 percent of the specified compressive strength and no single core falls below 75 percent of it.
+
+### The Engineer of Record shall determine the number and location of cores and shall direct the repair of core holes in accordance with [[sync/concrete-repair-and-restoration]].
+
+### The cost of investigating a low strength test shall be assigned as indicated in the datasheet.
+
+```datasheet
+label: Cost Responsibility for Investigation of a Low Strength Test
+type: radio
+options:
+ - "Contractor bears all investigation costs"
+ - "Owner bears the cost where the investigation establishes the concrete as adequate and the Contractor bears it otherwise"
+ - "Owner bears all investigation costs"
+default: "Owner bears the cost where the investigation establishes the concrete as adequate and the Contractor bears it otherwise"
+```
+
+### The Contractor shall not defer investigation of a low strength trend to the acceptance age where the early-age specimens have already shown it.
+
+### For a conventional portland cement mixture, the 7-day strength typically falls between 65 and 75 percent of the 28-day strength. A 7-day result well below that band is early warning that the acceptance test will fall short, while a mixture carrying a high proportion of slag cement or fly ash sits below the band legitimately and still reaches its specified strength at the acceptance age. {note}
+
+### Failure of the three-consecutive-test average and failure of a single test mean different things. A low running average says the mixture is centered too low and the proportioning or the plant control has to change; a single low test against a healthy average says one load or one set of specimens went wrong. Treating the two as the same event produces either an unnecessary coring program or an uncorrected mixture. {note}
+
+## Supplementary In-Place Testing {toc}
+
+### In-place test methods may be used to estimate strength for construction decisions before acceptance-age results are available, using rebound number in accordance with ASTM C805/C805M, penetration resistance in accordance with ASTM C803/C803M, or the maturity method in accordance with ASTM C1074.
+
+### An in-place method shall be correlated to standard-cured specimen results for the specific mixture before its results are relied upon.
+
+### In-place test results shall not be used as the basis for acceptance of concrete strength.
+
+### In-place methods measure a surface property or a temperature history and infer strength from a correlation. That correlation is mixture-specific and degrades with age, carbonation, surface moisture, and aggregate type, which is why these methods serve well for deciding when to strip a form and poorly for deciding whether a structure is adequate. {note}
+
+# Defective Work {toc}
+
+## The Contractor shall report to the Engineer of Record every defect discovered after form removal, including honeycombing, cold joints, voids, exposed reinforcement, and cracks, before any corrective work begins.
+
+## The Contractor shall not repair, patch, coat, or conceal a defect before the Engineer of Record has reviewed it and directed a disposition in writing.
+
+## Concealing a defect before review shall be grounds for rejection of the element.
+
+## The Engineer of Record shall make the initial determination whether a reported defect is cosmetic, repairable, or cause for removal and replacement.
+
+## Repairs directed by the Engineer of Record shall be executed in accordance with [[sync/concrete-repair-and-restoration]].
+
+## Surface defects attributable to finishing or curing shall be evaluated and remediated in accordance with [[sync/concrete-curing-and-finishing]].
+
+## The cost of removing and replacing concrete that fails to conform to this standard, and the cost of correcting the work of other trades disturbed by that removal, shall be borne by the Contractor, except where the nonconformance is caused by an act of the Owner or by a change directed in writing.
+
+## A defect found at form removal is evidence about a process, not only about one element. Honeycombing at the base of a wall says the lift depth or the vibrator reach was wrong and the next wall will look the same; a cold joint says the placement rate never matched the delivery rate. Reporting before repair is what preserves that evidence. {note}
+
+# Protection and Load Application {toc}
+
+## Curing of each placement shall begin and continue in accordance with [[sync/concrete-curing-and-finishing]].
+
+## Construction loads shall not be applied to any element until the strength required by [[sync/concrete-formwork]] for that loading condition has been demonstrated by field-cured specimens or by the maturity method.
+
+## Concrete surfaces shall be protected from impact, abrasion, staining by stored materials, and chemical spillage until the finish or covering scheduled for that surface is installed.
+
+## The condition of a completed concrete surface shall be documented before the operations of another trade begin over it, and damage caused by those operations shall be repaired at the expense of the party causing it.
+
+# Warranty {toc}
+
+## The Contractor shall warrant the concrete work against defects in materials and workmanship for the period indicated in the datasheet, measured from the date of substantial completion.
+
+```datasheet
+label: Warranty Period
+type: range
+unit: years
+options:
+ min: 1
+ max: 5
+ setpoints: [1, 2, 3, 5]
+default: 1
+```
+
+## The warranty shall cover strength deficiency, cracking attributable to the Contractor's means and methods, surface scaling within the exposure classes specified for the element, and delamination of concrete placed under this standard.
+
+## Where the parties disagree on the cause of a defect claimed under the warranty, the Engineer of Record shall make the initial determination.
+
+## Work repaired under the warranty shall carry a renewed warranty running from the date the repair is accepted, for the full original period or for the remainder of the original period, whichever ends later.
+
+## Distress arising from loading beyond the design basis, from exposure more severe than the exposure classes specified for the element, or from a mixture the Engineer of Record directed over the Contractor's written objection is a design matter rather than a construction defect. {note}