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TABLE 7 Non - Agitator Trucks Agitator Trucks 45 minutes 60 minutes 75 minutes* 90 minutes* *When a water reducing and retarding admixture (Type D or Type G) is used. 346 -7.7 Adding Water To Concrete at the Placement Site: Perform an initial slump before the addition of water at the job site. After adjusting the slump, perform a test to confirm that the slump of the concrete is within the target range as defined in Table 6. If the slump exceeds the target range but is within the tolerance range, that load may be accepted, but water added at the site will be reduced to maintain a slump within the target range on successive loads. If the slump is delivered within the target range, no water will be added to the load. Confirm with another test that the next load is within the target range after the addition of water at the placement site. Repeated incidents of concrete being placed outside the target range will result in revocation of that portion of the QCP. No concrete represented by plastic test results outside of the tolerance range will be accepted for placement. 346 -7.8 Sample Location: Obtain samples from the point of final placement. Where concrete buckets are used to discharge concrete directly to the point of final placement or into the hopper of a tremie pipe, samples will be obtained from the discharge of the bucket. When the concrete is discharged directly from the mixer into the bucket, with a minimal lapse of time before discharge of the bucket, samples may be obtained from the discharge of the mixer. Where conveyor belts, troughs, pumps, or chutes are used to transport concrete directly to the point of final placement or into the hopper of a tremie pipe, samples will be obtained from the discharge end of the entire conveyor belt, trough, pump, or chute system. Where concrete is placed in a drilled shaft or other element using a tremie pipe and a concrete pump, samples will be obtained from the discharge of the pump line at �! the location of the tremie hopper. Where a concrete pump is used to deposit concrete directly into a drilled shaft which is a wet excavation without the use of a tremie, ensure the discharge end of �I the pump line remains immersed in the concrete at all times after starting concrete placement, and the following procedure is followed: a. Obtain initial samples from the discharge of the pump line using the full length of pump line which will be required to start the placement. Ensure the plastic properties of the concrete sampled from the discharge of the pump line are within the target range. Obtain comparative initial samples from the discharge of the mixer delivering concrete to the pump in order to control the plastic properties of the mix. b. Obtain all other samples from the discharge of the mixer delivering concrete to the pump. Ensure the plastic properties of the concrete being delivered to the pump are within the allowable tolerance, except when necessary and approved by the engineer and based on comparative testing, to provide concrete meeting the Specification requirements at the end of the pump line. Describe concrete placement and sampling methods in the QCP. ulI' March 2007 01000 -101 03- 4122.D