The Grade of concrete construction is selected based on structural design requirements. Types of concrete mixes are
- Nominal mix
- Design mix.
- This concrete are those which are generally used for small scale construction and small residential buildings where concrete consumption is not high.
- Its takes care of factor of safety against various quality control problems generally occurring during concrete construction.
- This concrete are those for which mix proportions are obtained from various lab tests.
- Use of design mix concrete requires good quality control during material selection, mixing, transportation and placement of concrete.
- This concrete offers mix proportions based on locally available material and offers economy in construction if large scale concrete construction is carried out.
- Large concrete construction projects uses design mix concrete.
Selection of concrete grade
- Therefore, suitable grade of concrete can be selected based on structural requirements. Nominal mixes for grades of concrete such as M15, M20 and M25 are generally used for small scale construction.
- Large structures have high strength requirements, thus they go for higher grades of concrete such as M30 and above. The mix proportions of these concretes are based on mix design.