what is Aggregates?

Aggregates • Aggregates are the important constituents in concrete which give body to the concrete, provides bulk to the concrete , reduce shrinkage and effect economy. • Chemically inert materials but now it has been recognized that some of the aggregates are chemically active • Occupy 70–80 per cent of the volume of concrete • Needs to meet certain requirements for concrete to be workable, strong and durable • Usually aggregate must be of proper shape, clean, hard, strong and well graded.