| abstract |
Methods of controlling the durability of and/or the amount of air in concrete formulations that include combining cement, water, and optionally aggregates, admixtures and/or additives to form a cement mixture; and adding prepuff particles to the cement mixture to form a concrete formulation. The prepuff particles have an average particle diameter of from 0.2 mm to 3 mm, a bulk density of from 0.015 g/cc to 0.35 g/cc, an aspect ratio of from 1 to 3, and a smooth continuous outer surface. The cured and hardened concrete formulation typically has a relative dynamic modulus of at least 70% determined according to Procedure A of ASTM C666 (2003). The amount of air in the concrete typically increases over the amount of air in similar formulations not containing prepuff particles, as determined according to ASTM C231, based on the volume percent of prepuff. The concrete formulations can be used to make articles. |