Patent ID: 8815009
Filing Date: 2014-08-26
Classification: C04B

Abstract:
1. Method for making a sand composition for use in hydratable cementitious compositions, comprising (A) providing a plurality of manufactured sand particles having angular shapes and particle sizes whereby 5%-30% of said plurality of particles passes a 75 micron sieve, said manufactured sand particles bearing clay such that said clay-bearing manufactured sand has a methylene blue value of at least 0.5 mg/g; and (B) pre-treating said plurality of clay-bearing manufactured sand particles by intermixing them with at least one clay-mitigating polycation compound selected from the group consisting of epichlorohydrin dimethylamine and polydiallyldimethylamine, said clay-mitigating polycation compound being used in an amount of 0.01% to 0.5% based on weight of active polycation compound to weight of sand the clay-bearing manufactured sand particles being pretreated; and (C) blending the pretreated plurality of clay-bearing manufactured sand particles with a plurality of washed natural sand particles having generally spheroidal shapes and wherein the natural sand is washed to remove fines to the extent that at least 90 percent of the natural sand particles by weight are retained on a 75 micron sieve, whereby the ratio of the manufactured sand particles to the washed natural sand particles are in the range of 10-90:90-10.