The properties of concrete depends upon the proportions and type of its ingredients. A properly designed concrete mix is very durable. A good concrete mix should satisfy the following requirements:
- The concrete should be mixed thoroughly to from a homogeneous mix.
- Concrete should be compacted properly to prevent it from being porous.
- Sufficient curing of concrete is required for developing full strength.
- The water cement ratio should be appropriate, considering the strength and workability criteria.
- The concrete mix should be designed properly and should have all the ingredients in right proportions.
- The water used for mixing should be free from all harmful organic substances.
- The aggregate should be hard, durable and properly graded. For most R.C.C. works, 20 mm size of aggregate is suitable.
- The cement used for R.C.C. work should be of good quality and measured by weight only and not by volume.