Technical-Resources-for-Concrete-Contractors
Technical-Resources-for-Concrete-Contractors
Technical-Resources-for-Concrete-Contractors
Technical-Resources-for-Concrete-Contractors
Technical-Resources-for-Concrete-Contractors
Technical-Resources-for-Concrete-Contractors

Testing Fresh Concrete at Point of Delivery

ASCC Position Statement #20

Confusion occasionally arises at the project site when the pre-pour concrete conference does not adequately address the location of testing fresh concrete. ACI 301-99, “Specifications for Structural Concrete,” requires the slump and air content to be measured at the point of delivery. 

ACI 301 addresses the issues of measuring slump and air content at the point of placement in the Optional Requirements Checklist for Section
4.2.2.2: 

“It might be necessary at times to specify that the slump of concrete be determined at the point of placement rather than at the point of delivery. For example, pumped concrete is often specified to have slump measured at the end of the pumpline to preclude problems encountered with varying slump loss during pumping. This would provide for a slump higher than 4 in. at the point of delivery to obtain 4 in. slump at the end of the pumpline. Once the slump loss during pumping can be determined, acceptance or rejection of concrete based on slump can then be determined at the delivery point. For example, if a 1-1/2 in. slump loss during pumping has been established and confirmed by comparative testing, then the slump can be measured at the point of delivery to meet a 5-1/2 in. slump to meet the 4 in. slump requirement at the point of placement at the end of the pumpline.”

For the same reasons as described on the Optional Requirements Checklist to 4.2.2.2, it may be necessary to specify that air content be measured at the point of placement to account for loss of air content during pumping. Once the loss of air content during pumping is established, acceptance limits at the point of delivery can be determined.

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