5-169 aggregate week thereafter Material certifications / stressing calculations / calibration certifications Prior to beginning work (anticipate adequate time for review by QAI) Tensioning report The same work day Pre-placement inspection report Prior to the concrete placement Concrete batch slips The morning of the next work day Results of concrete testing The morning of the next work day Results of compressive strength testing (for release) The same work day Concrete temperature records Provide with compressive strength testing (for release) Nonconformance reports/repair procedures Within 24 hours of dis covery Results of compressive strength testing (for design strength) Prior to stopping curing Post-placement inspection report Within 48 hours of achieving d esign strength * The Contractor and QAI may, by mutual agreement, modify any p art of the schedule; however, failure to provide the documentation when required by the Fabrication Engineer will result in the product being deemed unacceptable. The Contracto r may perform testing in addition to the minimum required. The results of all testing s hall be made available to the Department.
535.08 Quality Assurance Quality Assurance (QA) is the preroga tive of the Department.
The QAI will perform acceptance sampling and testing and will w itness or review documentation, workmanship and testing to assure the Work is be ing performed in accordance with the Contract Documents. The QAI has the authority to reject materials and products that do not meet the Contract requirements, including Work rejected due to denial of access o r the lack of adequate notice of the beginning of production. The acceptance of material or workmanship by the QAI will not preclude subsequent rejection, if found unacceptable by the Department, at a later date.
535.09 Nonconforming Work Correct or replace nonconforming mat erial and/or
workmanship. Generate a nonconformance report (NCR) describing the nonconformance and the proposed corrective action; provide a copy to the QAI a nd forward a copy to the Fabrication Engineer for review. In the event that an item does not meet the Contract requiremen ts but is deemed suitable for use by the Department, said item may be accepted in accorda nce with Section 106.8, Non-Conforming Work, of the Standard Specifications. 5-170
535.10 Forms and Casting Beds Construct forms in accordance wi th the Working
Drawings. The forms shall be well constructed, carefully align ed and sufficiently tight to prevent leakage of mortar. R eject forms that do not maintain t he dimensions shown on the Working Drawings. Inspect the bulkheads after each cast and re pair or replace worn or damaged pieces. Seal wooden forms to prevent absorption of water. Apply and cu re the sealer in accordance with the manufacturer's product data sheet. Remove all paint, adherent material, foreign matter and debris prior to placing concrete. Apply a non-staining bond-breaki ng compound to the forms in acc ordance with the manufacturer's product data sheet . Solvent clean reinforcing s teel and strand contaminated with the bond-breaking compound.
535.11 Reinforcing Steel Fabricate, package, handle, store, pl ace, splice and repair
reinforcing steel in accordance with Section 503 of the Standar d Specifications. Accurately locate and securely a nchor the reinforcing steel to prevent displacement during concrete placement. Install and secure all reinforcing steel prior to beginning the concrete placement. The concrete cover shown on the reviewed Working Drawings shall be the minimum allowable cover. Use sufficient bar supports and spacers to ma intain the minimum concrete cover. The bar supports and spacers shall be made of a dielect ric material or other material approved by the Fabrication Engineer.
535.12 Voids and Inserts Voids shall be non-absorbent. The ou t-to-out dimensions of
the voids shall be within 2 percent of Plan dimensions. Repair damaged voids in a manner acceptable to the Fabrication Engineer. Store, handle and plac e voids in a manner that prevents damage. Accurately locate and securely anchor, securely cap and vent th e voids in the form. Any portion of a void that is displaced beyond the allowable dimens ional tolerances shall be cause for rejection of the slab or beam. Open the void drains immediat ely upon removing the product from the form. Recess inserts 1 inch, unless noted otherwise on the Plans. The Department is not responsib le for verifying the location of inserts or other hardware installed for the convenience of the Contractor.
535.13 Concrete New concrete mix designs and mix designs not p reviously approved by
the Fabrication Engineer shall be qualified by trial batches pr epared in accordance with AASHTO T 126 (ASTM C192). The test results shall demonstrate t hat the concrete meets 5-171 the requirements of the Plans and this Specification. If accel erated curing is to be used in production, the test specimens shall be similarly cured. The concrete mix design shall meet the following requirement s: Minimum cement content 658 lbs./cubic yard Water-cement ratio * 0.40 (maximum) Air entrainment 5-½ % to 7-½ % Allowable Slump Flow for Self- Consolidating Concrete (SCC) 20 inches to 30 inches Visual Stability Index(VSI) for SCC VSI of 0 or 1, per ASTM C16 11. If a mortar paste halo is present, it shall not exceed 0.25 inch. Corrosion inhibitor ** 3 gal. /c.y. (unless otherwise specifie d) Silica Fume (when used) 5% to 10% of cement content by weight Fly Ash (when used) 40% of cementitious material (maximum) Slag (when used) 50% of cementitious material (maximum) * For the purpose of calculating water cement ratios, one U.S . gallon of water shall be considered to weigh 8.34 pounds. ** The water in the corrosion inhibitor solution shall be inclu ded when calculating the water-cement ratio. The concrete mix design shall be proportioned so that the concr ete achieves transfer strength within twenty four hours of the completion of the plac ement if the release strength is 6,000 psi, or less. If two consecutive placements fail to m eet the above requirements, no further placements shall take place until corrective action is taken by the Contractor.
535.14 Concrete Placement Do not batch or place concrete until all the form(s) for any
continuous placement have been inspected and accepted by the QC I, and the QAI concurs. Test concrete in accordance with the following Standards: AASHTO T 22 (ASTM C39) Test Met hod for Compressive Strength of Cylindrical Concrete Specimens 5-172 AASHTO T23 (ASTM C31) Practice for Making and Curing Concrete T est Specimens in the Field AASHTO T141 (ASTM C172) Practice for Sampling Freshly Mixed Con crete AASHTO T152 (ASTM C231) Test Method for Air Content of Freshly Mixed Concrete by the Pressure Method AASHTO T196 (ASTM C173) Standard T est Method for Air Content of Freshly Mixed Concrete by the Volumetric Method ASTM C1064 Test Method for Temperature of Freshly mixed Portlan d Cement Concrete ASTM C1611 Standard Test Method for Slump Flow of Self-Consolid ating Concrete Test the first two loads of concrete for temperature, air entra inment and slump flow for SCC. If the first load is unacceptable, test the second load a s the first. Continue this process until two consecutive loads are acceptable. After two consecut ive loads are acceptable, the frequency of testing shall be a t the discretion of the QAI. If there is a change in the dosage rate of any admixture or a c hange of more than 5 F in mix temperature, then test the concrete for temperature, air en trainment and slump flow for SCC. Test every load of 1 cubic yard, or less, from a stationary mix er or 2 cubic yards, or less, from a transit mixer for temperature, air entrainment and slump flow for SCC, prior to placing the concrete in the forms. Perform all testing in the presence of the QAI. The QAI will d esignate the loads to be tested. Make cylinders used to determine release strength duri ng the last one-third of the placement. Place the concrete as nearly as possible to its final location. Control the depth of each lift in order to minimize entrapped air voids. The maximum dep th of an unconsolidated lift shall be 18 inches. Vibrate the concrete with internal or inte rnal and external vibrators. Do not use external vibrators, only. Insert internal vibrators ve rtically and penetrate the lower layer of concrete by at least 4 inches. Insert the vibrators i n the concrete to assure that the radii of action of the vibrator s overlaps. Hold the vibrators in position from 5 to 15 seconds; vibration time shall be reduced by 50 percent when placing SCC. Do not use vibrators to move concrete horizontally. Each lift of concrete shall have s ufficient plasticity to be consolidated with subsequent lifts. Do not re-temper the concrete with water after discharging has begun. The Contractor may add HRWR to the concrete after batching, if that practice c onforms to the manufacturer's product data sheet. Discard concrete that becom es unworkable. Do not use water or water-base d products to aid in finishing fr esh concrete. After the concrete has been placed and finished, and before the forms are covered, remove all concrete from projecting reinforcing steel. 5-173 Measure and record the concrete cover at each void location aft er void hold-downs have been removed. The QAI will indicate the number and location of the measurements.
535.15 Acceptance and Quality Control Testing of Concrete Acce ptance of structural
precast/prestressed units, for each day’s production, will be d etermined by the Department, based on compliance with this specification and satisfactory co ncrete testing results. At least once per week, the QAI will make 2 concrete cylinders (6 cylinders when the Contract includes permeability requirements) for use by the Department; cylinders shall be standard cured in accordance with AASHTO T23 (ASTM C31). The QAI will p erform entrained air content and slump flow testing, determine water-cement ratio an d determine temperature of the sampled concrete at the time of cylinder casting. All test ing equipment required by the QAI to perform this testing shall be provided in accordance wit h Standard Specification Section 502.041, Testing Equipment. In addition, the Contracto r shall provide a slump cone meeting the requirements of AASHTO T 119. Providing and mainta ining testing and curing equipment shall be considered incidental to the work and no add itional payment will be made. Quality Control concrete test cylinders shall be made for each day’s cast and each form bed used. Cylinders tested to determine strand release strengt h and design strength shall be field cured in accordance with AASHTO T23 (ASTM C31). 28 day c ylinders shall be standard cured. Record unit identification, entrained air cont ent, water-cement ratio, slump flow and temperature of the sampled concrete at the time of cyl inder casting If the Contractor fails to make enough cylinders to demonstrate that the product meets the Contract requirements, the product will be considered nonco nforming work. The compressive strength of the concrete will be determined by averaging the compressive strength of two test cylinders made from the same s ample. For the purpose of detensioning prestressed products, neither of the test cylinder s shall have a compressive strength less than the minimum required transfer strength. For the purpose of determining design strength, the average of two cylinders shall meet or exc eed the design strength, and the difference in strength between the two shall be no more tha n 10 percent of the higher strength cylinder. Perform compressive strength testing to determine transfer and design strength in the presence of the QAI. Cylinder tests not witnessed by the QAI w ill not be acceptable.
535.16 Curing by Moisture Retention Cure the concrete in accor dance with MNL 116,
Section 4.20. Moist cure the concrete until it has reached des ign strength. Do not use membrane- forming curing compounds without the appro val of the Fabrication Engineer. If membrane-forming curing compounds are authorized, follow the requirements of MNL 116 and the curing compound manufacturer’s published recommendations.