Concrete Practical

What must occur before a sample of concrete can be taken from a revolving drum mixture?

All water and admixtures must be added to the mixer

When sampling from a stationary or revolving drum mixer, what is collected and when is it taken during discharge?

In two or more portions of concreteAt regularly spaced intervalsFrom the middle of the batch

How are the sample portions obtained from the discharge stream of stationary or revolving drum mixer?

Repeatedly pass a receptacle through the entire discharge stream Completely divert the discharge stream into a sample container

Describe the procedure for collecting a sample from a paving mixer.

Discharge the contents of the paving mixerObtain samples from at least five different portions of the pile

5. What is the minimum size for a sample when strength test specimens are to be molded?

28 L [1ft^3]

6.What is the maximum allowable time between obtaining the first and final portions of the composite sample?

15 minutes

7. What action is required after the individual concrete samples have been transported to the place where tests are to be performed?

Combine and remix the samples with a shovel

8.What should be done if the concrete contains aggregate larger than is appropriate for the size of the molds or equipment being used?

Wet sieving

9. Start the tests for slump, temperature, and air content within how many minutes after obtaining the final portion of the composite strength sample?

5 minutes

10. Start molding specimens for strength tests within how many minutes after fabricating the composite sample?

15 minutes

11. From what must the concrete sample be protected?