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344 -2 . 1 . 1 Portland Cement : Cement shall conform to the requirements of the AASHTO or ASTM designations . Different brands of cement , cement of the same brand from different facilities or different types of cement shall be stored separately and shall not be mixed . Portland cements meeting the requirements of AASHTO M - 85 or ASTM C- 150 are allowed for LAP concrete . 344 -2 . 1 . 2 Coarse and Fine Aggregates : Aggregates shall meet current FDOT requirements except that source approval by the FDOT is not required . 344 -2 . 1 . 3 Water : Water shall meet current FDOT requirements . 344 -2 . 1 . 4 Chemical Admixtures : Chemical admixtures shall meet current FDOT requirements . Admixtures may be added at the dosage rates recommended by the manufacturer . 344 -2 . 1 . 5 Pozzolans and Slag : Pozzolans and Slag shall meet the current FDOT requirements . 344 -2 . 2 Material Storage : Use a concrete production facility that meets the following requirements . 344 -2 . 2 . 1 Cementitious Materials Storage : Provide a separate and clearly labeled weatherproof facility to store each brand or type of cementitious material without mixing or contamination . Provide a suitable , safe and convenient means of collecting cementitious material samples at each storage facility . 344 -2 . 2 . 2 Aggregate Storage : Provide suitable bins , stockpiles or silos to store and identify aggregates without mixing , segregating or contaminating different grades or types of materials . Identify aggregate type/gradation . Handle the aggregates in a manner to minimize segregation and meet the specification requirements when recovered from storage . Continuously and uniformly sprinkle coarse aggregate with water , for 24 hours preceding introduction into the concrete mix . Timers may be used to facilitate the sprinkling of aggregate stockpiles using an alternating on /off method . However , in no event shall the top surface of the stockpile be permitted to become dry prior to batching of concrete . Moisture probes may be used to determine the moisture content of the aggregate . Ensure that the accuracy of the probe is certified annually and verified weekly . Maintain stored aggregates in a well -drained condition to minimize free water content . Provide access for the Engineer to sample the aggregates from the recovery side of the storage facility . 344-3 Production , Mixing and Delivery of Concrete . 344 -3 . 1 Concrete Production Requirements : Use concrete production facilities certified by the National Ready- Mixed Concrete Association ( NRMCA) , approved by the FDOT . Produce concrete utilizing equipment that is in good operating condition and operated in a manner to ensure a consistent product . When moisture probes are not used , ensure that the concrete production facility determines the free moisture for the coarse and fine aggregates within two hours prior to each day' s batching . On concrete placements expected to exceed three hours , perform an additional moisture test approximately half way through the batching operations and adjust batch proportions accordingly . Ensure that the calibration of the measuring devices of the concrete production facilities meets the requirements of Chapter 531 of the Florida Statutes , and are in accordance with Chapter 9 . 2 of the FDOT Materials Manual . At least quarterly , ensure that all scales , meters and other weighing or measuring devices are checked for accuracy by a qualified representative of a scale company registered with the Bureau of Weights and Measures of the Florida Department of Agriculture . As an alternative , the producer may have 41 Technical Specifications F :\Public Works\ENGINEERING DIVISION PROJECTS\0744-8th St-US1 to 6th Ave\Admim\bid documents\0744 CONTRACT DOCUMENTS\Technical Specifications .doc