Sampling the concrete
Sampling should be in accordance with BS EN 12350-1, Testing fresh concrete. Sampling. This replaces BS 1881 Part 101.
Before sampling the concrete, it is important to make sure that it is fully mixed. The discharge from the ready mixed truck or pump should be uniform. At least 1 m3 of concrete should be discharged before a sample is taken. Samples should then be taken throughout the middle part of the load at the point of discharge and mixed together in a clean damp barrow or buckets. At least twice as much concrete as is needed should be sampled. Care should be taken to ensure that the concrete is not significantly wetted (from rain) or dried out (from strong sun or wind) as both will lead to low test results.