A STUDY OF NO-SLUMP CONCRETE.

A study was made of no-slump concrete, with primary consideration given to the effects of type of cement, use of admixtures, and shape of coarse aggregate on the properties of fresh and hardened concrete. The properties of fresh concrete that were observed included slump, workability, and air content. The properties of primary interest for hardened concrete were flexural strength and compressive strength. All of the mixes were designed to fall within the limits of zero to one inch of slump, and this was accomplished. The slump test is often used as the standard for the measure of the consistency of concrete. However, it was shown here that in the no-slump range this device was inadequate for measuring consistency. A variety of watercement ratios from 3.9 gallons per sack to 5.0 gallons per sack with a constant cement factor failed to produce a change in slump. In higher slump mixes, additional water in a given situation produces a change in slump.