(a) Samples for strength tests of each class of concrete placed each day shall be taken not less than once a day, or not less than once for each 50 cubic yards (345 m3) of concrete, or not less than once for each 2,000 square feet (186 m2) of surface area for slabs or walls. Additional samples for 7-day compressive strength tests shall be taken for each class of concrete at the beginning of the concrete work or whenever the mix or aggregate is changed.
(b) Loads used in design.
(c) Design work delegated to the contractor including applicable design criteria.
(a) Cementitious materials shall conform to the specifications in Table 18.104.22.168.1(a).
|Portland cement||ASTM C150|
|Blended hydraulic cements||ASTM C595, excluding Type IS (≥70) and Type IT (S ≥ 70)|
|Expansive hydraulic cement||ASTM C845|
|Hydraulic cement||ASTM C1157|
|Fly ash and natural pozzolan||ASTM C618|
|Slag cement||ASTM C989|
|Silica fume||ASTM C1240|
(a) Aggregates shall conform to (1) or (2):
(1) Normalweight aggregate: ASTM C33.
(2) Lightweight aggregate: ASTM C330.
(b) Aggregates not conforming to ASTM C33 or ASTM C330 are permitted if they have been shown by test or actual service to produce concrete of adequate strength and durability and are approved by the building official.
(a) Mixing water shall conform to ASTM C1602.
(b) Mixing water, including that portion of mixing water contributed in the form of free moisture on aggregates, shall not contain deleterious amounts of chloride ion when used for prestressed concrete, for concrete that will contain aluminum embedments, or for concrete cast against stay-in-place galvanized steel forms.
(a) Admixtures shall conform to (1) through (4):
(1) Water reduction and setting time modification: ASTM C494.
(2) Producing flowing concrete: ASTM C1017.
(3) Air entrainment: ASTM C260.
(4) Inhibiting chloride-induced corrosion: ASTM C1582.
(c) Calcium chloride or admixtures containing chloride from sources other than impurities in admixture ingredients shall not be used in prestressed concrete, in concrete containing embedded aluminum, or in concrete cast against stay-in-place galvanized steel forms.
(a) Requirements (1) through (11) for each concrete mixture, based on assigned exposure classes or design of members:
(1) Minimum specified compressive strength of concrete, fc'.
(2) Test age for demonstrating compliance with fc' if different from 28 days.
(4) Nominal maximum size of coarse aggregate not to exceed the least of (i), (ii), and (iii):
(i) one-fifth the narrowest dimension between sides of forms
(ii) one-third the depth of slabs
(5) For members assigned to Exposure Category F, air content from 22.214.171.124.
(6) For members assigned to Exposure Class C, applicable chloride ion limits for assigned Exposure Class from 126.96.36.199.
(8) For members assigned to Exposure Class S2 or S3, admixtures containing calcium chloride are prohibited.
(10) Requirement for submittal of the volumetric fractions of aggregate in lightweight concrete mixtures for the verification of λ value if used in design.
(b) At the option of the licensed design professional, exposure classes based on the severity of the anticipated exposure of members.
(c) The required compressive strength at designated stages of construction for each part of the structure designed by the licensed design professional.
(a) The required compressive strength at designated stages of construction for each part of the structure not designed by the licensed design professional shall be submitted for review.
(b) The maximum percentage of pozzolans, including fly ash and silica fume, and slag cement in concrete assigned to Exposure Class F3, shall be in accordance with Table 188.8.131.52(b) and (1) and (2).
(1) The maximum percentage limits in Table 184.108.40.206(b) shall include the fly ash or other pozzolans, slag cement, and silica fume used in the manufacture of ASTM C595 and C1157 blended cements.
|Cementitious materials||Maximum percent of total cementitious materials by mass|
|Fly ash or other pozzolans conforming to ASTM C618||25|
|Slag cement conforming to ASTM C989||50|
|Silica fume conforming to ASTM C1240||10|
|Total of fly ash or other pozzolans and silica fume||35|
|Total of fly ash or other pozzolans, slag cement, and silica fume||50|
(c) For concrete exposed to sulfate, alternative combinations of cementitious materials to those specified in 220.127.116.11(a)(7) are permitted if tests for sulfate resistance satisfy the criteria in Table 18.104.22.168(c).
|Exposure class||Maximum expansion strain if tested using ASTM C1012|
|At 6 months||At 12 months||At 18 months|
|S1||0.10 percent||No requirement||No requirement|
|S2||0.05 percent||0.10 percent||No requirement|
|S3||No requirement||No requirement||0.10 percent|
The 12-month expansion limit applies only if the measured expansion exceeds the 6-month maximum expansion limit.
(d) Steel fiber-reinforced concrete used for shear resistance shall satisfy (1) and (2):
(1) Conform to ASTM C1116.
(2) Contain at least 100 lb of deformed steel fibers per cubic yard of concrete.
(1) Can be placed readily without segregation into forms and around reinforcement under anticipated placement conditions.
(3) Conforms to strength test requirements for standard-cured specimens.
(b) Concrete mixture proportions shall be established in accordance with Article 4.2.3 of ACI 301 or by an alternative method acceptable to the licensed design professional. Alternative methods shall have a probability of satisfying the strength requirements for acceptance tests of standard-cured specimens that meets or exceeds the probability associated with the method in Article 4.2.3 of ACI 301. If Article 4.2.3 of ACI 301 is used, the strength test records used for establishing and documenting concrete mixture proportions shall not be more than 24 months old.
(a) Documentation of concrete mixture characteristics shall be submitted for review by the licensed design professional before the mixture is used and before making changes to mixtures already in use. Evidence of the ability of the proposed mixture to comply with the concrete mixture requirements in the construction documents shall be included in the documentation. The evidence shall be based on field test records or laboratory trial batches. Field test records shall represent conditions similar to those anticipated during the proposed Work.
(b) If field or laboratory test data are not available, and fc' ≤ 5000 psi, concrete proportions shall be based on other experience or information, if approved by the licensed design professional. If fc' > 5000 psi, test data documenting the characteristics of the proposed mixtures are required.
(c) If data become available during construction that consistently exceed the strength-test acceptance criteria for standard-cured specimens, it shall be permitted to modify a mixture to reduce the average strength. Submit evidence acceptable to the licensed design professional to demonstrate that the modified mixture will comply with the concrete mixture requirements in the construction documents.
(a) Cementitious materials and aggregates shall be stored to prevent deterioration or contamination.
(b) Material that has deteriorated or has been contaminated shall not be used in concrete.
(c) Equipment for mixing and transporting concrete shall conform to ASTM C94 or ASTM C685.
(d) Ready-mixed and site-mixed concrete shall be batched, mixed, and delivered in accordance with ASTM C94 or ASTM C685.
(a) Debris and ice shall be removed from spaces to be occupied by concrete before placement.
(b) Standing water shall be removed from place of deposit before concrete is placed unless a tremie is to be used or unless otherwise permitted by both the licensed design professional and the building official.
(d) Equipment used to convey concrete from the mixer to the location of final placement shall have capabilities to achieve the placement requirements.
(e) Concrete shall not be pumped through pipe made of aluminum or aluminum alloys.
(f) Concrete shall be placed in accordance with (1) through (5):
(1) At a rate to provide an adequate supply of concrete at the location of placement.
(2) At a rate so concrete at all times has sufficient workability such that it can be consolidated by the intended methods.
(3) Without segregation or loss of materials.
(4) Without interruptions sufficient to permit loss of workability between successive placements that would result in cold joints.
(5) Deposited as near to its final location as practicable to avoid segregation due to rehandling or flowing.
(g) Concrete that has been contaminated or has lost its initial workability to the extent that it can no longer be consolidated by the intended methods shall not be used.
(i) After starting, concreting shall be carried on as a continuous operation until the completion of a panel or section, as defined by its boundaries or predetermined joints.
(k) Top surfaces of vertically formed lifts shall be generally level.
(a) If supplementary tests of field-cured specimens are required to verify adequacy of curing and protection, the number and size of test specimens and the frequency of these supplementary tests.
(a) Concrete, other than high-early-strength, shall be maintained at a temperature of at least 50°F and in a moist condition for at least the first 7 days after placement, except if accelerated curing is used.
(b) High-early-strength concrete shall be maintained at a temperature of at least 50°F and in a moist condition for at least the first 3 days after placement, except if accelerated curing is used.
(c) Accelerated curing to accelerate strength gain and reduce time of curing is permitted using high-pressure steam, steam at atmospheric pressure, heat and moisture, or other process acceptable to the licensed design professional. If accelerated curing is used, (1) and (2) shall apply:
(d) If required by the building official or licensed design professional, results of tests of cylinders made and cured in accordance with (1) and (2) shall be provided in addition to results of standard-cured cylinder strength tests.
(1) At least two 6 × 12 in. or at least three 4 × 8 in. field-cured cylinders shall be molded at the same time and from the same samples as standard-cured cylinders;
(2) Field-cured cylinders shall be cured in accordance with the field curing procedure of ASTM C31 and tested in accordance with ASTM C39.
(e) Procedures for protecting and curing concrete shall be considered adequate if (1) or (2) are satisfied:
(1) Average strength of field-cured cylinders at test age designated for determination of fc' is equal to or at least 85 percent of that of companion standard-cured cylinders.
(2) Average strength of field-cured cylinders at test age exceeds fc' by more than 500 psi.
(b) Frozen materials or materials containing ice shall not be used.
(c) Forms, fillers, and ground with which concrete is to come in contact shall be free from frost and ice.
(a) If required by the design, locations and details of construction, isolation, and contraction joints.
(e) Surface preparation including intentional roughening if composite topping slabs are to be cast in place on a precast floor or roof intended to act structurally with the precast members.
(b) Except for prestressed concrete, construction joints in floor and roof systems shall be located within the middle third of spans of slabs, beams, and girders unless otherwise approved by the licensed design professional.
(c) Construction joints in girders shall be offset a distance of at least two times the width of intersecting beams, measured from the face of the intersecting beam, unless otherwise approved by the licensed design professional.
(a) Details required to accommodate dimensional changes resulting from prestressing, creep, shrinkage, and temperature.
(c) Details for construction of sloped or stepped footings designed to act as a unit.
(c) At locations where slab and column concrete placements are required to be integrated during placement, column concrete shall extend full slab depth at least 2 ft into floor slab from face of column and be integrated with floor concrete.
(d) Saw cutting in slabs-on-ground identified in the construction documents as structural diaphragms or part of the seismic-force-resisting system shall not be permitted unless specifically indicated or approved by the licensed design professional.
(a) ASTM designation and grade of reinforcement.
(d) Location and length of lap splices.
(e) Type and location of mechanical splices.
(f) Type and location of end-bearing splices.
(g) Type and location of welded splices and other required welding of reinforcing bars.
(h) ASTM designation for protective coatings of nonprestressed reinforcement.
(a) Mill test reports for reinforcement shall be submitted.
(b) Nonprestressed reinforcement with rust, mill scale, or a combination of both shall be considered satisfactory, provided a hand-wire-brushed representative test specimen of the reinforcement complies with the applicable ASTM specification for the minimum dimensions (including height of deformations) and weight per unit length.
(c) Prestressing reinforcement shall be free of mill scale, pitting, and excessive rust. A light coating of rust shall be permitted.
Table 22.214.171.124(a)—Tolerances on d and specified cover
|d, in.||Tolerance on d, in.||Tolerance on specified concrete cover, in.|
|≤ 8||±3/8||Smaller of:||—3/8|
|— (1/3) • specified cover|
|> 8||±1/2||Smaller of:||—1/2|
|— (1/3) • specified cover|
Tolerance for cover to formed soffits is —1/4 in.
(b) Tolerance for longitudinal location of bends and ends of reinforcement in accordance with Table 126.96.36.199(b). The tolerance for specified concrete cover in Table 188.8.131.52(a) shall also apply at discontinuous ends of members.
|Location of bends or reinforcement ends||Tolerances, in.|
|Discontinuous ends of brackets and corbels||±1/2|
|Discontinuous ends of other members||±1|
(b) Spiral units shall be continuous bar or wire placed with even spacing and without distortion beyond the tolerances for the specified dimensions.
(d) For longitudinal column bars forming an end-bearing splice, the bearing of square cut ends shall be held in concentric contact.
(e) Bar ends shall terminate in flat surfaces within 1.5 degrees of a right angle to the axis of the bars and shall be fitted within 3 degrees of full bearing after assembly.
(c) Offset bars shall be bent before placement in the forms.
(a) Welding of all nonprestressed bars shall conform to the requirements of AWS D1.4. ASTM specifications for bar reinforcement, except for ASTM A706, shall be supplemented to require a mill test report of material properties that demonstrate conformance to the requirements in AWS D1.4.
(f) For adhesive anchors, parameters associated with the characteristic bond stress used for design in accordance with 17.4.5, including minimum age of concrete, concrete temperature range, moisture condition of concrete at time of installation, type of lightweight concrete if applicable, and requirements for hole drilling and preparation.
(i) Required certifications for installers of adhesive anchors that are installed in a horizontal or upwardly inclined orientation to support sustained tension loads in accordance with 184.108.40.206 and 220.127.116.11.
(c) Pipes and fittings not shown in the construction documents shall be designed to resist effects of the material, pressure, and temperature to which they will be subjected.
(d) No liquid, gas, or vapor, except water not exceeding 90°F or 50 psi pressure, shall be placed in the pipes until the concrete has attained its specified strength.
(e) In solid slabs, piping, except for radiant heating or snow melting, shall be placed between top and bottom reinforcement.
(f) Conduit and piping shall be fabricated and installed so that cutting, bending, or displacement of reinforcement from its specified location is not required.
(a) Members shall be marked to indicate location and orientation in the structure and date of manufacture.
(b) Identification marks on members shall correspond to erection drawings.
(c) Design and details of lifting devices, embedments, and related reinforcement required to resist temporary loads from handling, storage, transportation, and erection shall be provided if not designed by the licensed design professional.
(d) During erection, precast members and structures shall be supported and braced to ensure proper alignment, strength, and stability until permanent connections are completed.
(3) Embedded items shall be maintained in the correct position while the concrete remains plastic.
(4) The concrete shall be consolidated around embedded items.
(a) Magnitude and location of prestressing forces.
(b) Stressing sequence of tendons.
(c) Couplers shall be placed in areas approved by the licensed design professional and enclosed in housings long enough to permit necessary movements.
(d) Burning or welding operations in the vicinity of prestressing reinforcement shall be performed in such a manner that prestressing reinforcement is not subject to welding sparks, ground currents, or temperatures that degrade the properties of the reinforcement.
(e) Prestressing force and friction losses shall be verified by (1) and (2).
(f) The cause of any difference in force determination between (1) and (2) of 26.10.2(e) that exceeds 5 percent for pretensioned construction or 7 percent for post-tensioned construction shall be ascertained and corrected, unless otherwise approved by the licensed design professional.
(h) If the transfer of force from the anchorages of the pretensioning bed to the concrete is accomplished by flame cutting prestressed reinforcement, the cutting locations and cutting sequence shall be selected to avoid undesired temporary stresses in pretensioned members.
(i) Long lengths of exposed pretensioned strand shall be cut near the member to minimize shock to the concrete.
(j) Prestressing reinforcement in post-tensioned construction shall not be stressed until the concrete compressive strength is at least 2500 psi for single-strand or bar tendons, 4000 psi for multistrand tendons, or a higher strength, if required. An exception to these strength requirements is provided in 26.10.2(k).
(k) Lower concrete compressive strength than required by 26.10.2(j) shall be permitted if (1) or (2) is satisfied:
(2) Prestressing reinforcement is stressed to no more than 50 percent of the final prestressing force.
(a) Requirement for the contractor to design, fabricate, install, and remove formwork.
(b) Location of composite members requiring shoring.
(c) Requirements for removal of shoring of composite members.
(a) Design of formwork shall consider (1) through (5):
(1) Method of concrete placement.
(2) Rate of concrete placement.
(3) Construction loads, including vertical, horizontal, and impact.
(4) Avoidance of damage to previously constructed members.
(5) For post-tensioned members, allowance for movement of the member during application of the prestressing force without damage to the member.
(b) Formwork fabrication and installation shall result in a final structure that conforms to shapes, lines, and dimensions of the members as required by the construction documents.
(c) Formwork shall be sufficiently tight to inhibit leakage of paste or mortar.
(d) Formwork shall be braced or tied together to maintain position and shape.
(a) Before starting construction, the contractor shall develop a procedure and schedule for removal of formwork and installation of reshores, and shall calculate the loads transferred to the structure during this process.
(b) Structural analysis and concrete strength requirements used in planning and implementing the formwork removal and reshore installation shall be furnished by the contractor to the licensed design professional and to the building official, when requested.
(c) No construction loads shall be placed on, nor any formwork removed from, any part of the structure under construction except when that portion of the structure in combination with remaining formwork has sufficient strength to support safely its weight and loads placed thereon and without impairing serviceability.
(e) The estimate of in-place concrete strength shall be based on tests of field-cured cylinders or on other procedures to evaluate concrete strength approved by the licensed design professional and, when requested, approved by the building official.
(f) Formwork shall be removed in such a manner not to impair safety and serviceability of the structure.
(g) Concrete exposed by formwork removal shall have sufficient strength not to be damaged by the removal.
(h) Formwork supports for post-tensioned members shall not be removed until sufficient post-tensioning has been applied to enable post-tensioned members to support their dead load and anticipated construction loads.
(i) No construction loads exceeding the combination of superimposed dead load plus live load including reduction shall be placed on any unshored portion of the structure under construction, unless analysis indicates adequate strength to support such additional loads and without impairing serviceability.
(a) A strength test shall be the average of the strengths of at least two 6 × 12 in. cylinders or at least three 4 × 8 in. cylinders made from the same sample of concrete and tested at 28 days or at test age designated for fc'.
(b) The testing agency performing acceptance testing shall comply with ASTM C1077.
(c) Qualified field testing technicians shall perform tests on fresh concrete at the job site, prepare specimens for standard curing, prepare specimens for field curing, if required, and record the temperature of the fresh concrete when preparing specimens for strength tests.
(d) Qualified laboratory technicians shall perform required laboratory tests.
(a) Samples for strength tests of each class of concrete placed each day shall be taken not less than once a day, or not less than once for each 50 cubic yards (38.2 m3) of concrete, or not less than once for each 2,000 square feet (186 m2) of surface area for slabs or walls. Additional samples for seven-day compressive strength tests shall be taken for each class of concrete at the beginning of the concrete work or whenever the mix or aggregate is changed.
(b) On a given project, if total volume of concrete is such that frequency of testing would provide fewer than five strength tests for a given concrete mixture, strength test specimens shall be made from at least five randomly selected batches or from each batch if fewer than five batches are used.
(a) Specimens for acceptance tests shall be in accordance with (1) and (2):
(1) Sampling of concrete for strength test specimens shall be in accordance with ASTM C172.
(2) Cylinders for strength tests shall be made and standard-cured in accordance with ASTM C31 and tested in accordance with ASTM C39.
(b) Strength level of a concrete mixture shall be acceptable if (1) and (2) are satisfied:
(1) Every arithmetic average of any three consecutive strength tests equals or exceeds fc'.
(2) No strength test falls below fc' by more than 500 psi if fc' is 5000 psi or less; or by more than 0.10fc' if fc' exceeds 5000 psi.
(c) If either of the requirements of 18.104.22.168(b) are not satisfied, steps shall be taken to increase the average of subsequent strength results
(d) Requirements for investigating low strength-test results shall apply if the requirements of 22.214.171.124(b)(2) are not met
(a) If any strength test of standard-cured cylinders falls below fc' by more than the limit allowed for acceptance, or if tests of field-cured cylinders indicate deficiencies in protection and curing, steps shall be taken to ensure that structural adequacy of the structure is not jeopardized.
(b) If the likelihood of low-strength concrete is confirmed and calculations indicate that structural adequacy is significantly reduced, tests of cores drilled from the area in question in accordance with ASTM C42 shall be permitted. In such cases, three cores shall be taken for each strength test that falls below fc' by more than the limit allowed for acceptance.
(c) Cores shall be obtained, moisture-conditioned by storage in watertight bags or containers, transported to the testing agency, and tested in accordance with ASTM C42. Cores shall be tested between 48 hours and 7 days after coring unless otherwise approved by the licensed design professional. The specifier of tests referenced in ASTM C42 shall be the licensed design professional or the building official.
(d) Concrete in an area represented by core tests shall be considered structurally adequate if (1) and (2) are satisfied:
(1) The average of three cores is equal to at least 85 percent of fc'.
(2) No single core is less than 75 percent of fc'.
(e) Additional testing of cores extracted from locations represented by erratic core strength results shall be permitted.
(f) If criteria for evaluating structural adequacy based on core strength results are not met, and if the structural adequacy remains in doubt, the responsible authority shall be permitted to order a strength evaluation in accordance with Chapter 27 for the questionable portion of the structure or take other appropriate action.
(a) Steel fiber-reinforced concrete used for shear resistance shall satisfy (1) through (3):
(1) The compressive strength acceptance criteria for standard-cured specimens
(2) The residual strength obtained from flexural testing in accordance with ASTM C1609 at a midspan deflection of 1/300 of the span length is at least the greater of (i) and (ii):
(i) 90 percent of the measured first-peak strength obtained from a flexural test and
(ii) 90 percent of the strength corresponding to .
(3) The residual strength obtained from flexural testing in accordance with ASTM C1609 at a midspan deflection of 1/150 of the span length is at least the greater of (i) and (ii):
(i) 75 percent of the measured first-peak strength obtained from a flexural test and
(ii) 75 percent of the strength corresponding to
(a) General progress of the Work.
(b) Any significant construction loadings on completed floors, members, or walls.
(c) The date and time of mixing, quantity, proportions of materials used, approximate placement location in the structure, and results of tests for fresh and hardened concrete properties for all concrete mixtures used in the Work.
(a) Placement of concrete.
(b) Tensioning of prestressing steel and grouting of bonded tendons.
(c) Installation of adhesive anchors in horizontal or upwardly inclined orientations to resist sustained tension loads in accordance with 126.96.36.199 and where required as a condition of the anchor assessment in accordance with ACI 355.4.
(b) Curing method and duration of curing for each member.
(c) Construction and removal of forms and reshoring.
(d) Sequence of erection and connection of precast members.