Aggregates

Aggregates are the major and important constituent of concrete. They form the body of the concrete as it occupies 70–80% of the volume of concrete. Although aggregates were originally considered to be inert material, they have recently been found to be chemically active to some extent. Cement is the only factory-made component, whereas aggregates (both coarse and fine) and water are naturally available materials.

Concrete can be considered as a two-phase material, viz., paste phase and aggregate phase. Paste phase is the role played by cement and water in concrete whereas aggregate phase is the role played by aggregates (both fine and coarse) in concrete. The requirement of paste phase has been dealt in previous chapter. Now the aggregates phase is discussed.