A lightweight ready-mix concrete composition that contains 8-20 volume
percent cement, 11-50 volume percent sand, 10-31 volume percent prepuff
particles, 9-40 volume percent coarse aggregate, and 10-22 volume percent
water, where the sum of components used does not exceed 100 volume
percent. 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 composition measured
according to ASTM C 143 is from 2 to 8 inches. After the lightweight
ready-mix concrete composition is set for 28 days, it has a compressive
strength of at least 1400 psi as tested according to ASTM C39.