Pyramids (3) The formula, the invention of stone
2006-4-10 · Imhotep had invented a water-based cement. Now, he had only to convert that cement into concrete. 6. LIMESTONE CONCRETE. His workers added more fossil shells, limestone rubble and silt from the river Nile, producing a …How concrete is made - material, manufacture, making, …Preparing Portland cement 1 The limestone, silica, and alumina that make up Portland cement are dry ground into a very fine powder, mixed together in predetermined proportions, preheated, and calcined (heated to a high temperature that will burn off impurities without fusing the ingredients).