Deval attrition test:A Deval attrition test is a test which is carried out to measure the rate of wear of a granular material i.e.
abrasion resistance value. One of the best examples of a material subjected to an attrition test are stones used in road construction, indicating the resistance of the material to being broken down under road traffic.
Percentage wear
Dorry abrasion test: Coefficient of hardness is calculated from Dorry abrasion test. It is an indication of the abrasion resistance i.e. resistance against the external weathering of aggregates.
It is given by, Coefficient of Hardness
Los Angeles test:Los Angeles machine or Los Angeles abrasion test on aggregates is used to measure the aggregate toughness and
abrasion resistance such as crushing, degradation and disintegration.
The principle of Los Angeles abrasion test is to produce abrasive action by use of standard steel balls which when mixed with aggregates and rotated in a drum for a specific number of revolutions also causes the impact on aggregates.
Maximum abrasion value for wearing course is 30% and for the base course in WBM is 50%.
As per IS 2386 (Part IV):1963, Aggregate abrasion value can be determined by Deval attrition test, Dorry abrasion test and Los Angeles test.