The natural river sand was the cheapest resources of sand. However the excessive mining of rive bed to meet the increasing demand for sand in construction industry has lead to the ecological imbalance in the state. Now the sand available in the riverbed is very coarse and contains very high percentage of silt and clay. The silt and the clay presence in the sand reduce the strength of the concrete and holds dampness. The natural river sand is the product of sedimentation. mica, coal, fossils and other organic impurities are present in the river sand above certain percentage which make the sand useless for concrete work.
COMPARISON BETWEEN RIVER SAND VS M-SAND
Comparison of impurities |
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River sand |
M sand |
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| Marine product | 2- 4% | Nil |
| Over-sized materials | 6-10% | Nil |
| Clay & Slit | 5-20% | Nil |
SIEVE ANALYSIS |
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IS SIEVE |
River sand (% passing) |
M sand (%age passing) |
%age passing for single sized aggregate of normal sand (IS 383 – 1970) zone II |
| 2.36 mm | 93.5 | 78.25 | 75 to 100 |
| 1.18 mm | 48 | 52 | 55 to 90 |
| 600 microns | 21 | 38 | 35 to 59 |
| 300 microns | 4 | 21 | 8 to 30 |
| 150 microns | 0.05 | 5 | 0 to 10 |