Improvements relating to the manufacture of building materials of the concrete type

摘要

Steam hardened concrete, porous or not is made from an aqueous mix containing at least one calciferous material of the group unslaked lime, slaked lime, cement and blast furnace slag, and also containing silicous material at least a part of which is fine grained and the volume weight of which increases on grinding, by dry grinding the silicous material with at least part of the calciferous material until at least 95 per cent but not all of such mixture passes through a screen having 63 micron apertures, specified silicous materials are fly ash or diatomaceous earth, but some reactive silica may also be included, in which case more calciferous material is added. Gypsum may also be present, added with the mixing water, and not ground with the calciferous material.