HYDRAULIC BINDERS AND BUILDING ELEMENTS FORMED OF NON- TRADITIONAL MATERIALS

摘要

ABSTRACTHYDRAULIC BINDERS AND BUILDING ELEMENTSFORMED OF NON-TRADITIONAL MATERIALSA process is disclosed for the formation ofhydraulic binders and building elements comprising from 70%ettringite and up to 30% calcium silicate hydrates.Ettringite is a very strong mineral and the product may beat least the equal in terms of mechanical properties ofPortland cement while not suffering shrinkage and expansionproblems. The process comprises mixing powdered sourcematerials of reactive CaSO4, CaO and Al2O3 with or withoutSiO3 with or without SiO2 and hydrating the intimate mixtureat a ratio in the range of 1 part powdered source materialsto 0.35-1 part water. Most conveniently, impure sourcematerial such as industrial by-products are used as theyhave been found to catalyse the hydration reaction.Further if gypsum is a powdered source material, in anatural, pure or chemical form, it is preferably calcinedsince such material sets quickly and gives early mechanicalstrength. A clinker of calcium sulphoaluminate may beproduced for use as a powdered source material.