Bricks of tuff or pumice sand - mfd. with admixture of cement and air inclusions

摘要

Blocks, hollow blocks and other shapes of bricks are made of tuff or pumice sand or dust with an admixture of cement. Gas, specially air inclusions, impart to the stone material a certain porosity with an open or closed-cell structure. The materials of the inclusions can be sawdust or fine-grained polystyrene foam or electrofilter ash at a rate of max. 15-20%. This finds a useful market for material which is otherwise waste. Not much power is needed for the manufacture of such bricks.