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344 -3 . 6 . 2 Concreting in Hot Weather : Meet the temperature requirements and special measures for mixing and placing concrete in hot weather as specified in Section 346 . When the temperature of the concrete as placed exceeds 75 ° F , incorporate in the concrete mix a water- reducing retarder or water reducer if allowed by Section 346 . Spray reinforcing steel and metal forms with cool fresh water just prior to placing the concrete in a method approved by the Engineer . Assume ail risks connected with the placing and curing of concrete . Although the Engineer may give permission to place concrete , the Contractor is responsible for satisfactory results . If the placed concrete is determined to be unsatisfactory , remove , dispose of, and replace the concrete at no expense to the Agency . 344 -3 . 7 Mixers : Ensure that mixers are capable of combining the components of concrete into thoroughly mixed and uniform mass , free from balls or lumps of cementitious materials , and capable of discharging the concrete uniformly . Operate concrete mixers at speeds per the manufacturer' s design . Do not exceed the manufacturer' s rated capacity for the volume of mixed concrete in the mixer , mixing drum , or container . 344 -3 . 8 Small Quantities of Concrete : With approval of the Engineer, small quantities of concrete , less than 3 yd 3 placed in one day and less than 0 . 5 yd placed in a single placement may be accepted using a pre - bagged mixture . The Agency may verify that the pre - bagged mixture is prepared in accordance with the manufacturer' s recommendations and will meet the requirements of this Specification . 344 -3 . 9 Sampling and Testing : 344 -3 . 9 . 1 Category 1 : The Engineer may sample and test the concrete at his discretion to verify its quality . The minimum 28 day compressive strength requirement forthis concrete is 2 , 500 psi . 344 -3 . 9 . 2 : Category 2 : Provide a statement of certification from the manufacturer of the precast element that the element meets the quality control and inspection testing requirements of the Contract Documents . 344-3 . 9 . 3 Category 3 : The Agency will randomly select a sample from each 200 yd or one day' s production to determine plastic properties and to make three 4 x 8 inch cylinders for testing by the Agency at 28 days to ensure that the design compressive strength has been met . The Agency may , at its discretion , test additional concrete samples to ensure compliance with the specifications . 344 -3 . 10 Records : Maintain the following records for review for at least 3 years after final acceptance of the project : 1 . Approved concrete mix designs . 2 . Materials source (delivery tickets , certifications , certified mill test reports ) . 3 . A copy of the scale company or testing agency report showing the observed deviations from quantities checked during calibration of the scales and meters . 4 . A copy of the documentation certifying the admixture weighing / measuring devices . 5 . For Non Structural LAP concrete the Agency will accept recent NRMCA , VMMB or FDOT inspection records certifying the plant or truck can produce concrete . In addition , documentation will be available at the plant or in the truck showing that action has been taken to correct deficiencies noted during the inspections . 43 Technical Specifications F :\Public Works\ENGINEERING DIVISION PROJECTS\0744-8th St-US1 to 6th Ave\Admim\bid documents\0744 CONTRACT DOCUMENTS\Technical Specifications .doc