| abstract |
Rapid-gelling binder vehicles are produced by admixing a small amount of a water-soluble alkaline ionic silicate with a colloidal amorphous silica aquasol and adjusting the resulting composition to a pH of from 5 to 9.5. The amount of alkaline ionic silicate added is within the range of from 0.083 to 1.67 moles per 1000 grams of binder vehicle exclusive of silica and is dependent on the concentration and median particle diameter of the colloidal silica, the concentration of neutral salts and the pH to which the composition is to be adjusted. A binder vehicle prepared in this manner gels within from 5 to 300 seconds to form a gel structure having an exceptionally high porosity, wide pore diameters and high strength and attrition resistance. |