Stone Dust

This should be acquired through crushing hard stones and the grading shall be inside the limit for Zone III of Table 3.

Coarse Sand

This should be either river sand or pit sand and should conform to the grading of Zone III of Table 3.

The silt or organic content in fine aggregate should not within any case exceed 8%. Placing a sample of sand in a 200 ml measuring cylinder tests the silt content. The volume of sample will be such which it fills up to the 100 ml mark. Clean water shall be added up to the 150 ml mark. Before adding water, dissolve a little salt (one teaspoon per half liter) within the water. Shake the mixture vigorously. Permit the contents to settle down for three hours. The height of the silt visible as a layer above the sand should be expressed as a percentage of the height of sand below.

Sand having more than the permutable percentage of silt shall be washed to bring down the silt content inside the specified limits.