Abstract: The present invention relates to a method of providing thermal insulation and fire-resistance to buildings, by filling voids or spaces in and around structural members with a low density thermally insulating and fire-resistant cementitious composition containing a high proportion of a relatively smooth-surfaced, vesicular, expanded perlite. The method includes placing a flexible, woven, fire-resistant bag in the space to be filled, so as to act as a containment vessel, pumping a cementitious composition into the bag to fill a space by conforming to the shape of the space, while the bag simultaneously contains the cementitious composition in the desired position, and allowing the composition to cure into a lightweight, fire-resistant, and thermally insulating concrete. The method is particularly useful in and directed to remedial, post-construction applications in occupied buildings.

Abstract: An admixture for a dense and durable concrete mix consisting essentially of diatomaceous earth and silica fume in the ratio of from 1 to 1 up to 1 to 8. Optionally, fly ash and lignosulfonate dispersant may be added to the admixture.

Abstract: A pumpable backfill grout which hardens into a controlled low strength material and an additive for making up such a backfill grout. The grout consists essentially of portland cement, a smooth surfaced vesicular expanded perlite, fly ash, fine aggregate, water, an air entraining agent, a quick dispersing thixiotropic suspending agent and a bentonite thickening agent.