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Classification of aggregates

Aggregates are classified as

  1. Fine aggregate
  2. Coarse aggregate

Fine aggregate

The material which passes through I.S. sieve No.480 [4.75mm] and retained on I.S. sieve No. 5 [0.05mm] is considered as fine aggregate e.g. natural sand, surkhi etc. according to the grain size, the sand is termed as follows.

Size Type of sand
0.06 to 1mm Very fine sand
1 to 3mm Harfine sand
3 to 4.75 Coarse sand

Coarse aggregate

The material which passes through an 80mm sieve and retained on I.S. sieve No.480 [4.75mm] is considered as coarse aggregate. E.g. pebbles, gravel, and if 30mm it is called fine gravel, and if 30 to 80mm is called course gravel. Depending on the size of course aggregate it is used for different works as follows.

Size Use
200 to 75mm Mass concrete foundation, dams
50 to 75mm Roadwork
24 to 50mm Plain concrete work
15 to 20mm R.C.C. works
10 to 12mm Thin R.C.C. section, curtain walls