METHODS OF PLACING CONCRETE

摘要

A method of placing a concrete compositions including a) combining 3 - 40 volume percent cement, 5 - 50 volume percent fine aggregate, 5 - 50 volume percent coarse aggregate, and 10 - 22 volume percent water; b) adding 1.5 - 40 volume percent of prepuff particles to form a concrete composition; and c) pumping the concrete composition to a point higher in elevation than the delivery point of the concrete to place the concrete. The concrete composition contains less than 30 volume percent of other light weighting aggregates and the prepuff particles have an average particle diameter of from 0.2 mm to 8 mm, a bulk density of from 0.02 g/cc to 0.64 g/cc, an aspect ratio of from 1 to 3. The slump value of the placed concrete measured according to ASTM C 143 is greater than 1 inch and the concrete has a density of from about 40 to about 135 lb./ft3.