Testing the slump of the concrete that arrives on your job site is the only way you can assure that the concrete you ordered is the concrete you received, and that it is ready to place through the pump. Accordingly, we recommend that you slump test every truck that arrives on the job site and notify your supplier that you will be doing so. This practice will go a long way towards ensuring that your project is successful.
Slump Test Procedures
PURPSTOSE OF TEST: To determine the consistency of fresh concrete and to check its uniformity from batch to batch.This test is based on ASTM C 143-74: Standard Test Method for Slump of Portland Cement Concrete. Also refer to ASTM172-71 Standard Method Sampling Fresh Concrete.
Take two or more representative samples—at regularly spaced intervals—from the middle of the mixer discharge; donot take samples from beginning or end of discharge. Obtain samples within 15 minutes or less.
Important: Slump test must be made within 5 minutes after taking samples.
Combine samples in a wheelbarrow or appropriate container and remix before making test.
Dampen slump cone with water and place it on a flat, level, smooth, moist, nonabsorbent, firm surface.
*Pearce can provide concrete in various slump ranges, depending on strength and workability needs. Ideal slump is in the 4-6" range. The slump test must be performed within 2 1/2 minutes after obtaining the composite sample.
Technician begins to fill mold in three equal layers.
Each layer is rodded 25 times to settle the concrete, before the next layer is added.
Full mold is ready to be pulled off to measure slump.
Technician must pull mold off within 3-7 seconds for accurate test, per ASTM standards.
Partial mix being revealed by removal of mold.
Full concrete mix now ready for measurement.
This mix shows an ideal slump of around 4.5" measured to the displaced center of the top surface of concrete.
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