specifications - FAACO - Federal Aviation Administration Contract ...

U. ZINC CHROMATE PRIMER:FTWIC-2235June, 20092.02 BATCH PLANT:Aluminum surfaces which contact or are embedded in concrete shall be coated with zincchromate primer. Primer shall be Tnemec "Tneme-Zinc" or approved equal.Batch plants shall be an established concrete batching facility meeting the requirements of theConcrete Plant Standards of the Concrete Plant Manufacturers Bureau.2.03 DELIVERY TICKETS:Delivery tickets are required and shall be per ASTM C94, Section 16.2.04 MIXING AND MIXING EQUIPMENT:A. Mixers may be stationary, truck, or paving mixers of approved design. They shall becapable of combining the materials into a uniform mixture and of discharging withoutmixture segregation. Stationary and paving mixers shall be provided with an acceptabledevice to lock the discharge mechanism until the required mixing time has elapsed. Themixers or mixing plant shall include a device for automatically counting the total numberof batches of concrete mixed. The mixers shall be operated at the drum or mixing bladespeed designated by the Manufacturer on the name plate.B. The mixing time for stationary mixers shall be based upon the mixer's ability to produceuniform concrete throughout the batch and from batch to batch. For guidance purposes,the manufacturer's recommendations, or one (1) minute for one (1) cubic yard plus 1/4minute for each additional cubic yard may be used. Final mixing time shall be based onmixer performance. Mixers shall not be charged in excess of the capacity specified bythe manufacturer.C. When a stationary mixer is used for partial mixing of the concrete (shrink mixed), thestationary mixing time may be reduced to the minimum necessary to intermingle theingredients (about 30 seconds).D. When a truck mixer is used, either for complete mixing (transit-mixed) or to finish thepartial mixing in a stationary mixer and in the absence of uniformity test data, each batchof concrete shall be mixed not less than 70 nor more than 100 revolutions of the drum, atthe rate of rotation designated by the manufacturer of the equipment as mixing speed. Ifthe batch is at least 1/2 cubic yard less than the rated capacity, in the absence ofuniformity test data, the number of revolutions at mixing speed may be reduced to no lessthan 50. Additional mixing shall be performed at the speed designated by theManufacturer of the equipment as agitating speed. When necessary for proper control ofthe concrete, mixing of transit-mixed concrete shall not be permitted until the truck mixeris at the site of the concrete placement. Truck mixers shall be equipped with accuraterevolution counters.E. Vehicles used in transporting materials from the batching plant to the paving mixers shallhave bodies or compartments of adequate capacity to carry the materials and to delivereach batch, separated and intact, to the mixer. Cement shall be transported from the03300-17