ABSTRACT
This chapter discusses the properties of materials used in reinforced concrete. The main materials in reinforced concrete are cement, aggregates, water, steel, and admixtures. In its simplest form, concrete is a mixture of adhesive paste and aggregates. The paste consists of cement and water. It coats the surface of the fine and coarse aggregates. Hydration, a chemical reaction, hardens the paste, which then gains strength to form the rock-like mass known as concrete. Concrete is plastic and malleable when freshly mixed and it is strong and durable when it hardens. Concrete is said to be malleable in the fresh state because it is pliable, ductile, and can be molded into any shape. Cement is a binder, a substance that sets and hardens and can bind other materials together. The various cements specified in section 3.2.1 of the code are Portland cement (ASTM C150); Blended hydraulic cement (ASTM C595); Expansive hydraulic cement (ASTM C845); Hydraulic cement (ASTM C1157); Slag cement (ASTM C989); and Silica fume (ASTM C1240). The most used cement in the construction of buildings is Portland cement, specified by ASTM C150.
