Aggregate is a collective term for the mineral materials such as sand, gravel, and crushed stone that are used with a binding medium such as water, bitumen, Portland cement, lime, etc. to form compound materials such as bituminous concrete and cement concrete.

Aggregates can either be natural or manufactured. Natural aggregates are generally extracted from larger rock formations through an open excavation e.g. quarry. Extracted rock is typically reduced to usable sizes by mechanical crushing. Manufactured aggregate is often a bye product of other manufacturing industries.

Aggregate is a collective term for the mineral materials such as sand, gravel, and crushed stone that are used with a binding medium such as water, bitumen, Portland cement, lime, etc. to form compound materials such as bituminous concrete and cement concrete.

Aggregates can either be natural or manufactured. Natural aggregates are generally extracted from larger rock formations through an open excavation e.g. quarry. Extracted rock is typically reduced to usable sizes by mechanical crushing. Manufactured aggregate is often a bye product of other manufacturing industries.

The coarse aggregates used in road construction should be able to show resistance to crushing under the Roller during construction and adequate resistance to surface abrasion under traffic. The strength of coarse aggregates is assessed by aggregate impact value test and aggregate crushing value test.

Resistance to wear or hardness is another essential property for aggregates used in road construction especially in wearing course.

A great strength of a road is derived from the mechanical interlocking of the aggregates which vary with the aggregate shape. Thus evaluation of shape of the aggregates, particularly with reference to flakiness and elongation is highly essential for good quality road works.

Aggregates may be classified as coarse aggregate and fine aggregate based on their sizes. Coarse/ fine aggregates shall conform to IS:383 and tests for conformity shall be carried out as per IS:2386, Parts I to VIII. For masonry work, fine aggregate (sand) shall conform to the requirements of IS:2116.

The Aggregate Section of Assam Road Research and Training Institute (ARR&TI) is one of the most important Section under ARR&TI and playing a vital role in the Construction Industry sector in Assam by carrying out laboratory quality control tests which are indispensible part of construction. The information about the Aggregate Section are given below -

Tests conducted at Aggregate Section with approved rates are as follows: