Cementitious materials include the many products that are mixed with either water or some other liquid or both to form a cementing paste that may be formed or molded while plastic but will set into a rigid shape. When sand is added to the paste, mortar is formed. A combination of coarse and fine aggregate (sand) added to the paste forms concrete.
Types of cementitious materials
Another class of cement is composed of calcined gypsum and its related products. Gypsum cement is widely used in interior plaster and for the fabrication of boards and blocks, but the solubility of gypsum prevents its use in construction exposed to any but extremely dry climates.
Oxychloride cement constitutes a class of specialty cement with unusual properties. Their cost prohibits their general use in competition with the cheaper cement; but for special uses, such as the production of spark-proof floors, they cannot be equaled.
Masonry cement or mortar cement are widely used because of their convenience. While they are, in general, mixtures of one or more of the above-mentioned cement with some admixtures, they deserve special consideration because of their economies.
Other cementitious materials, such as polymers, fly ash, and silica fume, may be used as a cement replacement in concrete. Polymers are plastics with long-chain molecules. Concretes made with them have many qualities much superior to those of ordinary concrete.
Silica fume, also known as micro silica, is a waste product of electric-arc furnaces. The silica reacts with limes in concrete to form a cementitious material. A fume particle has a diameter of only 1% of that of a cement particle.