Processed mineral additive for reducing concrete permeability and increasing strength

Abstract

A packaged concrete additive includes ground, expanded perlite with a volume weighted mean particle size of approximately 10-100 μm. The perlite optionally includes at least one additional component to improve workability and compensate for the natural tendency of expanded perlite to absorb water from the concrete mix. The additional component can include: water; a superplasticizer such as polycarboxylates, naphthalene sulfonate, and melamine sulfonate; or a hydrophobic compound, such as salts of fatty acids, fatty acids, silanes, and siloxanes. The additive is a flowable powder and for convenience of use it is packaged in a bag that can be directly added to the concrete batch and disappears on mixing. Concrete containing this additive displays superior properties to conventional concrete. Expanded perlite is a readily available raw material and the finished concrete is suitable where high strength structural concrete must withstand high temperatures.

Dependencies are inferred from the claim text.