ASTM C172/C173M - Standard Practice for Sampling Freshly Mixed Concrete Flashcards
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 PAVING mixer:
“Avoid _____________ with subgrade material or prolonged contact with an absorptive subgrade”
Contamination
When collecting concrete for strength testing, how much of a sample should be collected?
28L [1 cu. ft.]
When obtaining samples, “the elapsed time shall not exceed __________ between obtaining the first and the final portions of the composite sample”
15 minutes
“Sampling should normally be done as the concrete is delivered from the _____ to the conveying vehicles used to transport the concrete to the forms”
Mixer
When sampling from STATIONARY or TRUCK (revolving drum) mixers:
“Sample the concrete by collecting ___ or more portions taken at regularly spaced intervals during discharge of the ______ portion of the batch”
2,
Middle
When sampling from a CONTINUOUS mixer:
“Sample the concrete after the discharge of at least ___ L [__cu ft) of concrete”
140 L [5 cu ft]
C172 covers the sampling of concrete from five types of equipment, which are __________, __________, __________, __________ & __________
Stationary Mixers Paving Mixers Truck Mixers Continuous Mixers Open Top Mixers
“Perform sampling by passing the receptacle ________ ______ the discharge stream or by completely _________ the discharge into a sample container”
Completely through,
Diverting
“Do not obtain portions of the composite sample from the very _____ or ____ part of the batch discharge”
First,
Last
“In any case, do not obtain samples until after all of the _____ and any __________ have been added to the mixer”
Water,
Admixtures
When sampling from a CONTINUOUS mixer:
After obtaining the composite sample, “wait a minimum of ___ minutes and a maximum of ___ minutes before beginning tests”
(“because the mix water is input only seconds before discharge from the continuous mixer”)
Minimum = 2 minutes Maximum = 5 minutes
“Equipment for wet-sieving concrete shall be a sieve of suitable size and conveniently arranged and supported so that one can shake it rapidly by either _____ or __________ _____.
Hand,
Mechanical Means
When sampling from a TRUCK (revolving drum) mixer:
TRUE or FALSE
Regulate the rate of discharge of the batch by the size of the gate and not by the rate of revolution of the drum.
FALSE:
Regulate the rate of discharge of the batch by the rate of revolution of the drum and NOT by the size of the gate opening.
Start tests for slump, temperature, and air content within ___ minutes after obtaining the final portion of the composite sample.
5 minutes
