Sampling Freshly Mixed Concrete

Sampling by this practice covers procedures for obtaining representative samples, on which tests are to be preformed to determine _____ with quality requirements of the specifications under which the concrete is furnished.

Compliance

This practice covers sampling from 5 types of equipment, which are ____

Stationary, paving, revolving drum, continuous, and open top

The elapsed time between obtaining the first and final portions of a composite sample shall not exceed ____

15 min

T/F Portions of a composite sample shall be thoroughly remixed before beginning tests on sample

True

Start tests for slump, temperature, and air content within ____ after obtaining the final portion of the composite sample

5 min

Start molding specimens for strength tests within ___ after fabricating the composite sample.

15 min

The concrete sample must be protected from what 4 things?

Contamination, wind, sun, and rapid evaporation

The minimum size sample for making strength test specimens is ___

1 cubic foot

When sampling from a stationary mixer, the batch must be sampled at ____ or more regularly spaced intervals during discharge of the middle portion of the batch.

2

When sampling from a paving mixer, obtain samples from at least ___ different portions of the pile and combine them into one composite sample for test purposes.

5

When sampling from a revolving drum truck mixer, sample the concrete by collecting ___ or more portions take at regularly spaced intervals during discharge of the middle portion of the batch.

2

T/F Concrete samples from a truck mixer must be obtained before any water or admixtures are added to the mixer at the job site.

False

The composite sample from a truck mixer must be obtained from the ____ portion of the batch.

Middle

When the concrete contains aggregate larger than that permitted for a particular test method, the sample of concrete must be ____ before making the test.

Wet sieved