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11 Cards in this Set
- Front
- Back
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What must occur before a sample of concrete can be taken from a revolving drum mixer? |
All water and admixtures must be added to the mixer. |
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When sampling from a stationary or revolving drum mixer, what is collected and when is it taken during discharge? |
- In two or more portions - At regularly spaced intervals - From middle of the batch |
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How are sample portions obtained from the discharge stream from a stationary or revolving drum mixer? |
- Passing the receptacle through the discharge stream - Diverting the discharge stream into the receptacle |
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Describe the procedure for collecting samples from a paving mixer. |
- Discharge the the contents of the paving mixer - Obtain samples from 5 different portions of the pile |
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What is the minimum size for a sample when strength test specimens are to be made? |
1ft³ |
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What is the maximum allowable time between obtaining the first and final portions of the composite sample? |
15 minutes |
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What action is required after the individual concrete samples have been transported to the place where the tests are to be performed? |
Combine and remix with a shovel |
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What should be done if concrete contains aggregate larger than is appropriate for the size of the molds or equipment being used? |
Wet sieving |
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Start the test for slump, temperature, and air content within how many minutes after obtaining the final portion of the composite sample? |
5 minutes |
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Start molding specimens for strength tests within how many minutes after fabricating the composite sample? |
15 minutes |
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From what must the concrete be protected? |
- Sun, wind, and rapid evaporation - contamination |
