In most civil engineering structures, concrete is a basic engineering material. It stands out as a material of choice in construction because of its special features, among them being durability, ease and convenience of manufacture on location, mould ability into any shape and size due to its plasticity in green stage and the resultant hardening to attain unrivaled strength. All these are best brought out by application of informed concrete mix design,

Concrete mix design should always be implemented with utmost care and proper understanding while taking all the necessary precautions. A concrete mix design manual is available to enhance awareness among users about the above. Concrete is principally a composition of Portland cement, aggregates and water but in specific cases may contain chemical ad mixtures and other cementius materials.

Depending on the composition, the purpose and concrete design mix applied, concrete may contain en trapped air and may also be mixed in such a way as to deliberately entrap air. This is made possible by use of chemical ad mixtures or air-en training cement.

In concrete mix chemical ad mixtures are frequently used for various reasons among them being to accelerate, improve workability, reduce mixing water requirements, increase strength or alter some properties of the concrete itself.

Several factors determine the selection of concrete proportions including a balance between the operating budget, place ability requirements, strength, density and desired resultant appearance. Also, for a good concrete mix design one must critically analyze the following factors;

• What slump is needed

• What strength is required

• Need for entrained air

• What is the weather like (is it hot or cold)

• What size of aggregate is best for the structure to be constructed.

Concrete mix design is the most important consideration any serious contractor should factor The right concrete mix ratio can solve problems while the wrong one can create them. A good concrete mix design results in a concrete mix that is easily place able, strong as per application structural requirements, durable enough whether on wall or floor and should leave an impressive impression after the decorative pattens are created.

Concrete for building need to be designed to bring out desired qualities depending on the structure being constructed for instance durability, strength, workability, permeability, plump ability, shrinkage, pump ability, stamp ability and strain ability. Concrete mix design is the science of mixing constituent ingredients of concrete in the right proportions to achieve the required properties and in the most economical and professional way.

Concrete mix design is gradually becoming more and more relevant with advent of modern structures and high-rises demanding high grades of concentrate with high workability levels as well as economically viable and use of mineral ad mixtures for instance ash, slag, meta...