Presence of Deleterious Material

Deleterious materials are vegetable matter, soft particles, clay lumps, mica, coal, etc. which can adversely affect the performance of aggregates.

Specific Gravity and Water Absorption

Specific gravity of aggregates is an indirect measure of its strength. The higher the specific gravity, the denser is the rock and stronger is the aggregate.

Water absorption depends upon the voids in the rock. The more the water absorption, the greater is the voids content, and hence less strong is the aggregate. For concrete and bituminous pavements, a maximum value of 2 per cent of water absorption is specified.