ACI CERTIFICATION TEST
Start molding specimens for strength tests within how many minutes after fabricating the composite sample?
15 min
what is the minimum size for a sample when test specimens are to be molded?
28L
What is the maximum allowable time between obtaining the first and final portions of the composite sample?
15 min
Start the tests from slump, temperature, and air content within how many minutes after obtaining the final portion of the composite sample?
5 min
What must occur before a sample of concrete can be taken from the revolving drum mixer?
All of the water must be added to the mixer
What are the required steps for collecting a sample of concrete from a stationary or revolving drum mixer?
Collect two or more portions of concrete at regularly spaced intervals from the middle of the batch.
What is required after the concrete sample has been transported to the place where test are to be performed?
Combine and remix the sample with a shovel
Describe the procedure for collecting a sample of pavement concrete deposited on grade.
Discharge the contents of the paving mixer. Obtain samples from at least five different portions of the pile
Describe the different procedures that can be used to collect a sample of concrete from a stationary or revolving drum mixer.
Repeatedly pass a receptacle through the entire discharge stream. Completely divert the discharge stream into a sample container.
From what must the concrete sample be protected?
Sun, wind, and rapid evaporation. Contamination.
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
