Controlled Concrete Definition

WHAT IS THE DIFFERENCE BETWEEN NOMINAL MIX AND DESIGN MIX CONCRETE?

Mix design is a process of selecting suitable ingredients and determining their relative proportions with the objective of producing concrete of having certain minimum workability, strength and durability as economically as possible.

Concrete

A mix design can be designed in two ways as explained below

1. Nominal Mix
2. Design

NOMINAL MIX

It is used for relatively unimportant and simpler concrete works. In this type of mix, all the ingredients are prescribed and their proportions are specified. Therefore there is no scope for any deviation by the designer. Nominal mix concrete may be used for concrete of M-20 or lower. The various ingredients are taken as given in the table below

Grade	Max. quantity of dry Aggregates per 50 kg of cement	Fine Aggregate to Coarse Aggregate Ratio, by mass	Max. Quantity of water in litres
M-5	800	Generally 1:2 but may varies from 1:1.5 to 1:2.5	60
M-7.5	625	45
M-10	480	34
M-15	330	32
M-20	250	30