specifications - FAACO - Federal Aviation Administration Contract ...

FTWIC-2235June, 20096. Laboratory tests on trial mixes shall show a 28-day strength higher than thestated minimum 28-day strength per ACI 318, Table 5.3.2.2. From thesepreliminary tests, the ratios between 7-day and 28-day strengths shall beestablished to determine at seven (7) days the strengths necessary to satisfy therequired 28-day strengths. The 7-day trial mix strength test results shall besubmitted to the Contracting Officer at least 14 days in advance of the 28-daystrength tests. The final results of the 28-day compressive strength tests shall besubmitted to the Contracting Officer at least ten (10) days prior to the scheduledbeginning of concrete placement approved by the Contracting Officer prior to theplacement of any concrete.7. Two mix designs shall be designed for each class of concrete that contains a highrange water reducer. Both mix designs shall be designed for this project usingmaterials that are to be used in the concrete. Mix designs from previous projectsshall not be acceptable. Concrete mix designs which are to have high rangewater reducing admixtures shall have the trial mix designed without theadmixture. Laboratory test results shall show that the mix design meets all otherrequirements of the specification without the admixture. After the initial trialmix design is tested, another mix design shall be proposed using the sameportions in the initial mix design with the addition of the admixture. Testing ofthe concrete shall be performed under the guidance of the admixturemanufacturer's representative to determine dosage, addition times, andcompatibility with other admixtures and mixture constituents. In addition to thetest performed in the first trial mix, the second mix, with admixture added, shallhave tests performed and results tabulated that show slump retention for a 90minute time period, temperature control for 90 minutes, as well as compressivestrengths, and entrained air.F. TESTING:1. GENERAL:a) Tests shall be required throughout the work to monitor the quality ofconcrete. Samples shall be taken in accordance with ASTM C-172.b) The Contracting Officer may waive these requirements on concreteplacements of ten (10) cubic yards or less. However, evidence shall befurnished showing a design mix which meets the specifications.c) Testing of the materials, ready mix, transit mix or central plant concretewill be as specified in Section 01400 QUALITY CONTROL. Providehousing for the curing and storage of test specimens and equipment. Noconcrete shall be placed without a Contracting Officer at either the plantor at the project site.03300-4