Abstract: Materials with exceptional shock attenuating properties are chemically bonded ceramics having densities that range from 30 to 160 lb/cubic foot (0.48 to 2.56 g/cc) and porosities of 20% to 80%. The materials are chemically bonded ceramic composites based on Portland cement, silica fume, various hollow fillers, and may include a dispersing agent, any of a variety of fibers and water.

Abstract: The temperatures at which the cementitious composite materials described in U.S. Pat. No. 4,482,385 can be used as tool or mold materials are extended by a treatment which comprises heating said composite materials to a temperature sufficient to expel free and adsorbed water from the concrete portion of the cementitious composite and thereafter refilling the resulting pores with an organic monomer or prepolymer and then crosslinking said impregnant to form an organic polymeric network in the inorganic composite material.

Abstract: Cementitious composite materials having high strength, vacuum integrity, good thermal properties and low coefficient of thermal expansion are prepared from a mixture of(1) a high strength cement matrix, and(2) a filler component, comprising a metal fiber.These composites are useful in the manufacture of molds and tools for forming metals and plastics. A preferred composite mixture comprising Portland cement, chemically reactive silica particles, inorganic oxide particles, a cement superplasticizer, an irregularly shaped aggregate, metal fibers, and water. The mixtures preferably contain chemically reactive silica fume particles and reactive silica particles such as crystalline silica or quartz particles or a vitreous/glassy form of silicon. The mixtures preferably comprise stainless steel fibers and stainless steel aggregate. High nickel steel and silicon carbide can be used as aggregate in applications requiring low coefficient of thermal expansion.