Cement is a kind of fine grinding material. When mixed with water, the cement will become plastic colloid. This kind plastic colloid can harden not only in the air but also in the water. And it also can bond the stone and sand firmly together and form a firm stone shape water gelled material. Cement is inorganic non-metallic material which is one kind of the largest used building materials and engineering materials. It widely used in building, water conservancy, road, petroleum, chemical industry and military project.