Aggregate fine

Fine aggregate is inert or chemically inert material, most of which passes a 4.75 mm IS sieve and contains no more than 5% coarse material. They can be classified as follows:

1. Natural sand: Fine aggregate resulting from the natural disintegration of rocks and which has been deposited by streams or glacial agencies.
2. Crushed stone sand: Fine aggregate produced by crushing of hard stone.
3. Crushed gravel sand: Fine aggregate produced by crushing of natural gravel.

The fine aggregates serve the purpose of filling all the open spaces in between the coarse particles. Thus, it reduces the porosity of the final mass and considerably increases its strength. Usually, natural river sand is used as a fine aggregate. However, at places, where natural sand is not available economically, finely crushed stone may be used as a fine aggregate.