Fine aggregate is on of the major constituents of concrete which can influence concrete mix design substantially. Various factors such as fine aggregate fineness modulus, moisture content, specific gravity, and silt content affect the mix proportions of concrete. Fineness modulus specifies how much fine aggregate is required in a given mix design.
Fine aggregate moisture content influences the mix proportion substantially. It specifies the amount of water that may be added to subtracted to the mixture. Mix design of concrete cannot be carried out without specific gravity of fine aggregate, and higher specific gravity produced stronger concrete. Finally, the presence of silt in sand would increase water demand in concrete mixture and may reduce concrete strength.
1. Fineness Modulus
It is one of the factors that influence concrete mix design since it controls the proportion of sand in concrete mixture. The overall fineness of sand is given by factor called fineness modulus, and it is found by sieve analysis based on ASTM C 33/ M33 specifications or any other applicable standards. The fineness modulus of sand varies from 2 to 4.