ABSTRACT
Portland cement concrete is a composite material made by combining cement, supplementary cementing materials, aggregates, water, and chemical admixtures in suitable proportions and allowing the resulting mixture to set and harden over time. Because hardened concrete is a relatively brittle material with a low tensile strength, steel reinforcing bars and sometimes discontinuous fibers are used in structural concrete to provide some tensile load-bearing capacity and to increase the toughness of the material. In this chapter, we deal with some of the basic constituents: cements, aggregates, water, steel reinforcement, and fiber reinforcement. Chemical admixtures and supplementary cementing materials (often referred to as mineral admixtures) are covered in Chapter 2. It must be emphasized that choosing the appropriate
constituent materials for a particular concrete is a necessary, but not sufficient, condition for the production of high-quality concrete. The materials must be proportioned correctly, and the concrete must then be mixed, placed, and cured properly (Chapter 6). In addition, there must be careful quality control of every part of the concrete-making process. This requires full cooperation among the materials or ready-mixed-concrete supplier, the engineer, and the contractor.
