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SUBARTICLE 346 - 7 . 4 (Page 330) is deleted and the following substituted : 346-7. 4 Concreting in Cold Weather : Do not mix concrete when the air temperature is below 45 °F and falling. Mix and place concrete when the air temperature in the shade , and away from artificial heat, is 40°F and rising. Protect the fresh concrete from freezing until the concrete reaches a minimum compressive strength of 1 , 500 psi unless the concrete is to be heat cured. The requirements of concreting in cold weather are not applicable to precast concrete placement operations occurring in a temperature controlled environment . SUBARTICLE 346-7 . 6 (Page 33 1 ) is deleted and the following substituted: 346-7. 6 Transit Time : Ensure compliance with the following maximum allowable time between the initial introduction of water into the mix and depositing the concrete in place : TABLE 6 Non-Agitator Trucks Agitator Trucks 45 minutes 60 minutes 75 minutes * 90 minutes * *When a water-reducing and retarding admixture (Type D, Type G or Type II) is used. SUBARTICLE 346-7 . 7 (Page 331 ) is deleted and the following substituted : 346-7. 7 Adding Water to Concrete at the Placement Site : Perform an initial slump test before the addition of water at the jobsite . If the slump , as delivered, is outside the tolerance range , reject the load. If the slump is within the tolerance range, that load may be adjusted by adding water provided the addition of water does not exceed the water to cementitious materials ratio as defined by the mix design . After adjusting the slump, perform a slump test to confirm the concrete is within the slump tolerance range . Perform a slump test on the next load to ensure the concrete is within the slump tolerance range . Do not place concrete represented by slump test results outside of the tolerance range . ARTICLE 346 - 8 (Page 331 ) is deleted and the following substituted : 346-8 Plastic Concrete Sampling and Testing. QC tests include air content, temperature , slump , and preparing compressive strength cylinders for testing at later dates . In addition , calculate the water to cementitious materials ratio in accordance with FM 5 - 501 for compliance to the approved mix design . Ensure that each truck has a valid mixer identification card issued by the Department, the revolution counter on the mixer is working properly, and calibration of the water dispenser has been performed within the last twelve months and verify batch weights within required limits of the mix design . Reject any concrete batches that are delivered in trucks that do not have mixer identification cards . The Contractor may remove the mixer identification cards when a truck mixer is discovered to be in noncompliance . When the mixer identification card is removed for - 121 - FPID ( S ) : 423186 - 1 - 58 -01