MCA ORAL EXAM QUESTIONS WITH
ANSWERS |LATEST UPDATE .
What must occur before a sample of concrete can be taken from a revolving drum mixer? - correct
Answers -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? - correct Answers -In two or more portions of concrete, at regularly spaced intervals, and
from the middle of the batch
How are the sample portions obtained from the discharge stream of a stationary or revolving drum
mixer? - correct Answers -Repeatedly pass a receptacle through the entire discharge system &
completely divert the discharge stream into a sample container
Describe the procedure for collecting a sample from a paving mixture - correct Answers -Discharge the
contents of the paving mixture and obtain samples from at least 5 different portions of the pile
What is the minimum size for a sample when strength test specimens are to be molded? - correct
Answers -28 L (28ft^3)
What is the maximum allowable time between obtaining the first and final portions of the composite
sample? - correct Answers -15 min
What action is required after the individual concrete samples have been transported to the place where
tests are to be performed? - correct Answers -Combine and remix the samples with a shovel
What should be done if the concrete contains aggregate larger than is appropriate for the size of the
molds or equipment being used? - correct Answers -Wet sieving
Start the tests for slump, temperature, and air content within how many minutes after obtaining the
final portion of the composite sample? - correct Answers -5 mins
ANSWERS |LATEST UPDATE .
What must occur before a sample of concrete can be taken from a revolving drum mixer? - correct
Answers -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? - correct Answers -In two or more portions of concrete, at regularly spaced intervals, and
from the middle of the batch
How are the sample portions obtained from the discharge stream of a stationary or revolving drum
mixer? - correct Answers -Repeatedly pass a receptacle through the entire discharge system &
completely divert the discharge stream into a sample container
Describe the procedure for collecting a sample from a paving mixture - correct Answers -Discharge the
contents of the paving mixture and obtain samples from at least 5 different portions of the pile
What is the minimum size for a sample when strength test specimens are to be molded? - correct
Answers -28 L (28ft^3)
What is the maximum allowable time between obtaining the first and final portions of the composite
sample? - correct Answers -15 min
What action is required after the individual concrete samples have been transported to the place where
tests are to be performed? - correct Answers -Combine and remix the samples with a shovel
What should be done if the concrete contains aggregate larger than is appropriate for the size of the
molds or equipment being used? - correct Answers -Wet sieving
Start the tests for slump, temperature, and air content within how many minutes after obtaining the
final portion of the composite sample? - correct Answers -5 mins
