ABSTRACT
Mix design is the process of selecting the proportions of cement, water, fine and coarse aggregates and, if they are to be used, additions and admixtures to produce an economical concrete mix with the required fresh and hardened properties. The required hardened properties of the concrete result from the structural design process, and are therefore provided to the mix designer. The main part of the method is concerned with the design of mixes incorporating Portland cement, water and normal-density coarse and fine aggregates only, and with characteristic cube strengths of up to about 70 MPa. The cement and other binder constituents are usually the most expensive components, and ‘economical’ usually means keeping its/their content as low as possible, without, of course, compromising the resulting properties. For a particular cement and aggregate type, the concrete strength at a given age is assumed to be governed by the free water: cement ratio only.
