5-316 SECTION 542 – HIGH PERFORMANCE CONCRETE, RAPID SET
542.01 DESCRIPTION . This work shall consist of designing, furnishing, and placing a high early
strength, high performance, Portland cement concrete for structures and incidental construction . The Portland cement concre te may consist of a homogeneous mixture of cement, fine aggregate, coarse aggregate, water, admixtures, and pozzolans, proportioned and mixed according to these specifications.
542.02 MATERIALS . Materials shall meet the material requirements specified in Subsection 501.02 and
the following subsections: High Early -Strength Portland Cement ................................ ................................ ........ 701.0 3
542.03 CLASSIFICATION AND PROPORTIONING . Concrete shall meet the requirements specified in
Table 542.03A and shall be used as shown on the Plans. TABLE 542.03A – HIGH PERFORMANCE CONCRETE, RAPID SET PROPERTIES Min. 28 -Day Compressive Strength (psi) Max. W/CM Ratio 1 Max. VSI 2 Slump Limit Spread Limit Air Content Limits Max. Free Shrinkage Max. 56 -Day Surface Resistivity 3 5,000 TBD 1 N/A 4 TBD 5 7.0% ± 1.5% 0.040% Low 1 The maximum W/CM ratio shall be determined by the Contractor as established by mix qualification testing. During production, the W/CM ratio shall be less than or equal to the W/CM ratio from the approved qualification mix. See Subsection 542.03(b) . The W/CM ratio shall be rounded to two decimal places in accordance with ASTM E29 . 2 For SCC mixes, visual stabi lity index (VSI) as determined in accordance with ASTM C1611 . 3 The Contractor shall determine the surface resistivity in accordance with Subsection 542.03( b)(3). 4 The mix shall not exhibit segregation. If the mix does exhibit segregation, the load shall be rejected . If the spread is equal to or exceeds 20 inches, the mix shall be classified as SCC mix. 5 For SCC mixes, the Contractor shall determine the spread target and limits in accordance with Subsection 542.03(b)( 4). The spread shall be maintai ned within the determined spread limits for the placement. The mix shall not exhibit segregation. If the mix does exhibit segregation or exceeds the upper spread limit, the load shall be rejected . and subsequent loads shall be tested by the Contractor until the mix meets the allowable limits. The Engineer may perform a J -ring test at the time of placement if blocking is a concern. 5-317 If a nominal maximum aggregate size is not specified, the Contractor shall determine the nominal maximum aggregate size using guidance from ACI 211.1 . In no case shall the maximum aggregate size exceed 1/5 of the narrowest dimension between sides of the fo rms, 1/3 the depth of slabs, or 3/4 of the minimum clear spacing between individual reinforcing bars, bundles of bars, or pre -tensioning strands unless approved by the Engineer. The Contractor may use industry methods to develop gradations not specified in Section 704 that are better optimized to satisfy the required concrete performance characteristics. If the Contractor is using a combined gradation, they shall provide the method or methods of how they will monitor gradation, the limits of the gradation r anges, and the frequency of monitoring. Lightweight fine aggregate may be used to replace up to 30% of the volume of normal weight sand. The gradation of the lightweight fine aggregate shall conform to the requirements of AASHTO M 195 . The lightweight fine aggregate shall be conditioned for enough time to fully saturate the material. The stockpile shall be constructed so that the moisture content is uniform throughout the pile. The stockpile will be allowed to drain for 12 hours to 15 hours immediately prio r to use, unless an alternate procedure is approved by the Structural Concrete Engineer. The Contractor shall state the method, duration and procedure used to confirm that the material is at or above its saturated surface dry (SSD) value, by weight, throug hout the pile. The use of chlorides or admixtures containing chlorides is prohibited. All admixtures will be considered incidental to the work and included in the Contract unit price of the concrete. The concrete materials may be proportioned using the abs olute volumes method in accordance with the specified requirements. The volumetric proportioning method , such as that outlined in ACI 211.1 or other approved volumetric proportioning methods, shall be employed in the mix design. Prior to placing concrete on the project (or prior to the trial pour, whichever occurs first), the Contractor shall submit for approval the single mix design formulation that satisfies all mix design qualification requirements and testing for the class of concrete specified. The mi x designs shall be submitted to the Structural Concrete Engineer at the Agency’s Materials Testing and Certification Section Central Laboratory. The Structural Concrete Engineer may require a minimum of 8 weeks for testing, review, and approval of new mix designs. No class of concrete shall be placed on a project, including the trial pour, until the mix design is approved. If the proposed performance concrete mix design fails to meet the qualification requirements, the Contractor shall submit a revised mix design formula in writing to address the mix qualification deficiencies of the original failed mix design. Review of the revised mix design formula by the Structural Concrete Engineer will be completed within 14 calendar days. 5-318 (a) Mix Design Informat ion. The mix design shall contain the following information:
1.Class of concrete.
2.Type of mix, conventional or self -consolidating concrete (SCC).
3.Saturated surface dry or dry weights (specify which).
4.Aggregate types, sources, specific gravities, and absorption values.
5.28 day design compressive strength, psi.
6.Cementitious content and the amount of each, pounds per cubic yard.
7.Air content lower limit, percent.
8.56 day surface resistivity value.
9.Determined spread lower l imit and upper limit for SCC.
10.Maximum water/cementitious materials (W/CM) ratio.
11.Volumetric quantities of each material in the mix design.
12.Design unit weight of the mix.
13.Chemical admixture types, brand names, and dosages. Concrete test mix or mixes shall be used to obtain the test results where applicable. All wet testing shall be done by personnel with current ACI Concrete Field Testing Technician Grade I certifications. All other tests shall be performed by a laboratory t hat is accredited by AASHTO re:source or the Concrete and Cement Reference Laboratory (CCRL) in the particular test method, or as allowed by the Engineer.
b.Mix Qualification Tests . The following mix qualification tests shall be performed. The minimum air content value and the maximum water/cementitious materials ratio of the material used to pass the mix qualification tests shall become the minimum air content value and the maximum water/cementitious materials ratio allowed during production. 5-319 (1) The free shrinkage rate of the concrete shall be tested in accordance with Subsection 501.03(b)(1) .
2.The compressive strength of the concrete shall be measured based on the requirements of AASHTO T 22 for 3, 7, 14, and 28 day standard cured cylinders.
3.The surface resistivity of the concrete shall be measured in accordance with Subsection 501.03(b)(4) .
4.For SCC mixes, the Contract or shall determine the lower and upper spread limit in accordance with Subsection 501.03(b)(5) .
c.Alkali -Silica Reactivity . The alkali -silica reactivity (ASR) of each type of aggregate shall be measured in accordance with Subsection 501.03(c) . Test results shall be submitted with the mix design.
d.Mix Design Approval and Changes . After the mix design furnished by the Contract or has been reviewed and approved by the Structural Concrete Engineer, no changes to the mix design will be allowed. If a source change is requested due to a change in product or material name that does not include any significant change in product formula tion or material characteristic, and this is substantiated by the product or material supplier in writing, re -testing is not required. No new materials shall be incorporated without prior written approval of the Engineer. In no case shall concrete from mor e than one mix design be permitted to be used during the same pour without prior written approval of the Engineer. The approved mix design will be allowed consecutive re -approval if no material proportioning or material sources have changed from the previo us year’s approved mix design and the mix design is submitted with updated aggregate properties and volumes adjusted accordingly. The aggregate properties shall be tested annually. Aggregate property values will be valid for 14 months from the date tested. The properties to be tested include, but are not limited to, specific gravity and absorption. The mix design shall be accompanied by the previously completed and accepted mix qualification test data and any applicable updated test information. The submitt al shall also include all applicable quality control test results and all requests for variance from the material requirements of these specifications.
e.Proprietary Mix Designs . A proprietary concrete mix design meeting the same performance requirement s may also be considered for use. 5-320 542.04 BATCHING . Batching shall meet the requirements of Subsection 501.04 .
542.05 MIXING AND DELIVERY . Mixing and delivery shall meet the requirements of Subsection
501.05 .
542.06 QUALITY CONTROL . The Contractor shall provide assistance, equipment, materials, and
curing for field sampling and testing as required by the Engineer. All costs shall be included in the Contract unit prices under Section 631 . The Engineer shall per form all acceptance sampling and testing in accordance with the Agency’s Quality Assurance Program . The Contractor shall perform all on -site quality control (QC) sampling and testing. The person performing the QC sampling and testing shall have, as a minim um, current ACI Concrete Field Testing Technician Grade I Certification.
a.Trial Batch . Between 21 and 7 calendar days prior to the first placement, the Contractor shall produce and place a 2 cubic yard trial batch, at a location agreed upon by the Contr actor and the Engineer. The purpose of this trial batch is to demonstrate that the mix is capable of producing the wet test results within the specified ranges. The Engineer shall be given a minimum notice of 7 calendar days prior to the trial batch pour. The trial batch shall be poured in the presence of the Engineer and the Structural Concrete Engineer. The trial batch shall be produced and poured in the same manner, estimated concrete temperature, and time frames that will occur during construction. For SCC the spread shall be within ± 3 inches of the target spread, but still be within the established spread range limits for SCC. The J -ring test will be performed for SCC mix, and the difference between the J -ring and spread test shall not be greater than 2 inches. The Contractor shall provide qualified personnel to test spread, air content, and temperature of the trial batch. A trial batch will be required for each mix design used on the project. If SCC will be used in work with a sloped finished surface, the Contractor shall produce a mock - up during the trial batch to demonstrate that the mix can be finished with the sloped surface.
b.Sampling . Sampling for tests shall be performed in accordance with the requirements of AASHTO R 60 or other procedures approved by the Agency. Sampling shall be done at the point of placement or as close to it as practical.
1.Changes . Any time that there is a change in admixture dosage outside of the allowable tolerances, whether modified at the batc h plant or at the site, additional QC sampling and testing shall be performed on the modified load prior to incorporating the concrete into the work. 5-321 (2) Beginning of Load Sampling . Beginning of load sampling is sampling for QC testing purposes that is taken before 15% of the load has been discharged. Beginning of load sampling shall be performed as required by the Engineer, or as needed to ensure that the concrete meets the Contract requirements at the point of placement. The QC personnel shall monitor the placement operation and adjust the mix accordingly to ensure that the material being incorporated into the work meets Contract requirements.
c.Slump Tests . Slump tests shall be made in accordance with AASHTO T 119 .
d.Spread Tests . Spread tests for SCC mixes shall be performed in accordance with ASTM C1611, Procedure B . The concrete inside the cone shall not be tamped.
e.Visual Stability Index (VSI) Tests . VSI tests for SCC mixes shall be performed in accordance with ASTM C1611, Appendix X.1 and sh all be performed on each completed spread test.
f.Air Content Tests . Air content tests shall be made in accordance with the pressure method specified in AASHTO T 152 . For SCC mixes, the specimens shall be fabricated in accordance with ASTM C1758.
g.Compressive Strength Tests .
1.General Requirements . The number of compressive strength tests performed for acceptance will be as specified in the Materials Sampling Manua l. The Engineer may order additional tests as deemed necessary. Compressive test cylinders shall be made in accordance with the requirements of AASHTO R 100 and tested for compressive strength in accordance with the requirements of AASHTO T 22. For SCC mixes, the specimens shall be fabricated in accordance with ASTM C1758.
2.Categories of Testing .
a.Acceptance Testing . Acceptance testing uses specimens to determine the compliance with requirements for the project. All test cylinders used for quality acceptance testing shall be stored in an approved curing box until they are shipped to the Agency’s Materials Testing and Certification Section Central Laborat ory. 5-322 b. Job Control Testing . Job control testing uses specimens to determine whether adequate curing procedures are being followed and for early form removal or early loading of structure.
1.All job control specimens shall be stored on the structure and shall receive the same curing and protection from the elements as the concrete that they represent up until 24 hours before anticipated testing of specimens.
2.The maturity method may be used as an alternative to compressive strength testing for estimating the concrete strength. The procedures of ASTM C1074 shall be followed for the maturity method except as noted below:
i.For ASTM C1074, Section 8.1 , there shall be a minimum of 17 cylinders cast. Two of the 17 shall have temperature sensors embedded in them to be used for monitoring. ii. For ASTM C1074 , Section 8.4 , there shall be 3 cylinders tested for each test age. iii. For ASTM C1074, Section 8.4 , for rapid set concrete mixes the test ages shall be 12 hours, 1 day, 2 days, 7 days, and 28 days. The Contractor may adjust or add test ages if approved by the Engineer. All temperature measuring devices shall be verified or calibrated on a 12 month basis, or sooner if there are questions about the ir accuracy. The devices shall have an accuracy of ± 2° F. At least two temperature sensors shall be embedded each day in each pour. One sensor shall be placed where maturity is expected to develop the slowest at, or near, an exposed outer edge, and a second sensor shall be placed in the concrete poured from the last load of the day. Sensors shall be placed 2 inches to 4 inches from any existing concrete or an exposed outer edge. The temperature sensing end of the monitor shall not be placed in direct contact with reinforcing materials or other elements that will protrude through the surface of the concrete. The Contractor shall submit the proposed locations to the Engineer for review and approval. 5-323 c. Specimen Curing Requirements . Specimen curing requireme nts shall be as stated in the specifications or as directed by the Engineer. If not specifically stated, the curing shall be as specified in Table 542.06A . TABLE 542.06A – CONCRETE SPECIMEN CURING REQUIREMENTS Testing Category Number of Specimens Curing Location Acceptance See the Materials Sampling Manual Curing box Job control 2 per test On structure
h.Concrete Temperature . Concrete temperature tests shall be conducted in accordance with ASTM C1064 .
542.07 WEATHER AND TEMPERATURE LIMITATIONS . Weather and temperature limitations shall
be as specified in Subsection 501.07 .
542.08 FORMS . Forms shall meet the requirements of Subsection 501.08 .
542.09 PLACING CONCRETE . Placing concrete shall be performed as specified in Subsection 501.09 .
542.10 PUMPING . Pumping shall meet the requirements of Subsection 501.11 .
542.11 CONSTRUCTION JOINTS . Const ruction joints shall meet the requirements of Subsection
501.12 .
542.12 EXPANSION JOINTS . Expansion joints shall meet the requirements of Subsection 501.13 .
542.13 CONCRETE FINISHING . Concrete finishing shall meet the requirements of Subsection 501.14 .
542.14 Curing Concrete .
a.General Requirements . Water for use in curing concrete shall conform to the requirements of Subsection 745.01 . The effective cure time shall be only the time that the concrete has been maintained in a wet condition with the co ncrete surface temperature above 50°F. If the concrete is not maintained in a wet condition or the concrete surface temperature drops below 50°F, it shall not be counted as effective cure time. The cure period will be extended 4 hours for every 1 hour the concrete is below 50°F, beginning when the concrete temperature is raised to or exceeds the minimum curing temperature. 5-324 Regardless of the curing medium specified, the entire surface of the newly placed concrete shall be kept damp. This shall be achieve d by applying water with a nozzle that atomizes the flow so that a mist and not a spray is formed. The moisture shall not be applied under pressure directly upon the concrete and shall not be allowed to accumulate in a quantity sufficient to cause a flow or washing of the surface. The atomized flow shall be applied continuously until the surfaces can be covered by the specified curing mediums. The curing method shall be applied within 15 minutes of the completion of the finishing process. Unless otherwise specified in the Contract, concrete shall be wet cured until it has reached the minimum 28 -day compressive strength, verified by testing of job control specimens.
b.Curing Methods . All expo sed surfaces of newly placed concrete shall be cured by one of the following specified methods:
1.Burlap Curing . The entire exposed surface of the concrete shall be covered with two layers of approved burlap that has been pre -soaked with water. The burlap shall then be covered with a lapped layer of white polyethylene sheeting. Once the concrete superstructure has hardened sufficiently, a stream of water, applied with a soaker ho se or similar device, shall be run continuously under the polyethylene sheeting until the cure period is complete.
2.Pre-Dampened Cotton Mats . The entire exposed surface of the concrete shall be covered with a blanket of cotton mats that has been pre -dampened with water. The mats shall be maintained in a damp condition until the curing period is complete.
542.15 LOADING OF CONCRETE . After the concrete has been placed and the finishing operations
concluded, it shall not be walked on or disturbed in any ma nner, including the removal of forms, until curing is complete as specified in the Contract. A portable compression testing machine calibrated in accordance with ASTM C39, Section 5 shall be provided by the Contractor and available on -site for cylinder tes ting of field -cured cylinders for construction progress. There shall also be a hand -held grinding stone included with the compression testing machine. The hand -held grinding stone will be used to grind the top of the cylinders to relieve any sharp projecti ons on the cylinder surface. All testing and equipment shall conform to ASTM C39 . Testing will be performed, and equipment operated by, qualified Agency personnel. The individual shall be trained in the operation of the machine by the owner or representati ve of the machine who is proficient in the operations and functions of the machine. 5-325 If an independent lab is proposed to be used to test the field -cured cylinders instead of a portable compression testing machine, the Contractor shall submit the following documentation:
a.Calibration records of the compression machine in accordance with ASTM C39, Section 5 .
b.Proof that the compression machine meets the requirements of ASTM C39 .
c.Evidence of proficiency of the technician who will be performing the test methods. The Agency at any time reserves the right to perform an independent proficiency test of the technician for the test methods used and a review of the testing facility.
542.16 METHOD OF MEASUREMENT . The quantity of High Performa nce Concrete, Rapid Set to be
measured for payment will be the number of cubic yards of concrete placed in the complete and accepted work, as determined by the prismoidal method using dimensions shown on the Plans or as directed by the Engineer. The quanti ty of concrete will exclude the volume of steel or other stay -in-place forms and form filling materials. No deductions will be made for the volume of concrete displaced by steel reinforcement, structural steel, expansion joint material, scuppers, weep hole s, conduits, tops of piles, scoring, chamfers, or corners, inset panels of 1 -1/2 inches or less in depth, or any pipe less than 8 inches in diameter.
542.17 BASIS OF PAYMENT . The accepted quantity of High Performance Concrete, Rapid Set will be
paid for a t the Contract unit price per cubic yard. Payment will be full compensation for performing the work specified, including designing the mix, performance of trial pours, satisfactory finishing and curing. Payment will also be full compensation for furnishing all forms, materials, including joint filler and bond breaker, labor, tools, admixtures, and equipment, including automatic temperature recording units, trial batches, and incidentals necessary to complete the work. The cost of heating materials and prote cting the concrete against cold weather, and any additional cost for cement, will not be paid for separately but will be considered incidental to High Performance Concrete, Rapid Set. The cost of furnishing testing facilities and supplies at the batch plan t and the setting of inserts, benchmarks, and bridge plaques furnished by the Agency will not be paid for separately but will be considered incidental to High Performance Concrete, Rapid Set. Costs for all materials, labor, and incidentals for steel or oth er stay -in-place forms and form filling materials will not be paid for separately, but will be considered incidental to High Performance Concrete, Rapid Set. 5-326 Payment will be made under: Pay Item Pay Unit 542.1000 High Performance Concrete, Rapid Set ................................ .................... Cubic Yard 5-327 SECTIO N 543 – CONTRACTOR -FABRICATE D PRECAS T CONCRET E STRUCTURE 543.0 1 DESCRIPTION . This work shall consist of manufacturing, transporting, handling, and erecting precast concrete structure components fabricated by the Contractor at a location other than a PCI or NPCA certified precast concrete facility. 543.0 2 MATERIALS . Materials sh all meet the material requirements specified in Subsection 501.02 , Subsection 507.02 , and Subsection 540.02 . Concrete shall meet the material requirements specified in Subsection 540.05 . 543.0 3 GENERA L FABRICATIO N REQUIREMENTS . Unless noted otherwise her ein, Contractor - fabricated precast concrete (CFPC) shall meet the requirements of Section 501 , Section 507 , and Section 540. 543.0 4 SUBMITTALS . As soon as practical after award of the Contract, all required information shall be prepared and submitted. Fa brication drawings and erection plans shall be submitted as separate submittals. If the Contractor proposes a different configuration than what is provided in the Plan s then a complete copy of the structural design calculations for the CFPC shall be submitted accompanying the construction draw ings in accordance with Subsection 105.06 . The design calculations shall substantiate that the proposed precast concrete satisfie s the design parameters of the Contract. The applicable design code will be the AASHTO LRFD Bridge Design Specifications unless indicated otherwise in the Contract . Fabrication drawings for the precast concrete shall be submitted in accordance with Subsect ion 105.06 . In addition to the requirements for fabrication draw ings in Subsection 105.06 , the following shall also be included:
a.The concrete mix design in accordance with Subsection 540.04(a) .
b.Dimensions and tolerances of the sections to be fabric ated.
c.The location of reinforcing steel, splices, welded wire fabric, mechanical bar connectors, and inserts. Reinforcing steel material lists, material designations, and bending details shall also be included.
d.The type of concrete surface finish and how the finish will be obtained .
Source: Vermont Standard Specifications for Construction, 2024 Edition. Pages 730–740 of 1,380.