In general the sand particle should be coarser and have minimum silt contents. The silt contents should not be more than 4%. The quality of the sand has more impact on the strength of the structure inspite of the quantity of the cement used. 1) If there is more silt in coarse sand, the strength of cement mortar is reduced from 1 % to 30%. 2) If you take best quality coarse sand, it will give maximum strength
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