MIX DESIGN OF CONCRETE USING DIFFERENT METHODS

Concrete is an extremely versatile engineering material used in most of the civil engineering structures and like other engineering materials needs to be designed for certain desirable properties in fresh as well as hardened state. Properties desired in plastic state are ¿ workability, cohesiveness and initial set retardation, and that in hardened state are ¿ strength, imperviousness and durability.¿ The process of selecting suitable ingredients of concrete and determining their relative amounts with the objective of producing a concrete of the required strength, durability, and workability as economically as possible is said to be the concrete mix design¿. The cement pastes consist of Portland cement, water, and air either in the form of naturally entrapped air or intentionally entrained air bubbles. The inert materials are composed of aggregates. The basic ingredients of concrete are cement, coarse aggregate, fine aggregate and water. In addition to these chemical and mineral admixtures are also added in concrete in recent years.