Patent ID: 7699929

Claim:
A pre-cast and pre-stressed construction article containing a lightweight concrete composition comprising from 10 to 90 volume percent of a cement composition, from 10 to 90 volume percent of particles having an average particle diameter of from 0.2 mm to 3 mm, a bulk density of from 0.028 g/cc to 0.48 g/cc, an aspect ratio of from 1 to 3, and have a continuous outer layer, from 0 to 50 volume percent of aggregate, and less than one percent by weight with respect to total weight of the composition of air-entraining agents; wherein the sum of components used does not exceed 100 volume percent; wherein the concrete composition has a density of from about 90 to about 130 lb./ft 3 ; and wherein after the lightweight concrete composition is set for seven days, has a compressive strength of at least 1700 psi as tested according to ASTM C39.