Concrete testing interval

[derecha1]

What is a reasonable interval (test/CY) to test concrete(4 cylinders for compressive strength, air, and slump)?

Is this dependent on the size of the pour?

Let me know what your experiences are?

 

[BigH]

See Thread592-98784 in the Concrete Engineering General Discussion Forum.

 

[concreteguru]

CSA and ASTM specifications spell out frequency of testing fairly well. When I am having verification cylinders done to insure that nothing has changed from the original trial batch on the project, I would require that cylinders, slump, air, unit weight be done every 60 cubic yards for vertical placements and every 125 cubic yards for pavements. The sampling is done completely at random so no bias in choosing a truck for testing is introduced. Slump and air tests are done first and if they are in compliance with specifications, beams and or cylinder casting follow. If slump or air are not found to be within specified limits, the load is rejected, the production plant is notified and another truck is selected for test.