Abstract: A packaged concrete additive includes ground, expanded perlite with a volume weighted mean particle size of approximately 10-100 ?m. 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.

Abstract: A concrete additive includes expanded perlite with a volume weighted mean particle size of approximately 10-100 ?m. The perlite further 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 can be made in the form of a flowable powder or a flowable slurry. Concrete containing this additive displays superior properties to conventional concrete, including extremely high thermal resistance and high strength, low chloride ion permeability, and good early strength. The expanded perlite is a readily available raw material and the finished concrete is extremely cost effective for applications where a high strength structural concrete must withstand high temperatures.