Abstract: A method of making a porous refractory article and a dispersion of particles in a liquid carrier, the method involving forming a dispersion of particles in a liquid carrier, introducing gas into the dispersion, removing the liquid carrier to provide a solid article having pores derived from the bubbles and wherein the dispersion has a critical viscosity below the level at which the introduction of gas cannot take place and above the level which entrapped gas bubbles will tend to escape and with the dispersion having the same critical viscosity.

Abstract: Lightweight concrete roof tiles are produced by extruding a latex/cement/lightweight aggregates/water mix in a prescribed sequence. The composition comprises:(a) 45-65 parts by weight of an acrylic latex emulsion;(b) 130-180 parts by weight of a cement;(c) 360-400 parts by weight of expanded shale lightweight aggregates; and(d) 50-75 parts by weight of additional water.This lightweight concrete roof tile of the present invention is about half the weight and about the same strength, and absorbs the same amount of water of conventional roof tiles.