Los Angeles Abrasion test | Test for road aggregates

Los Angeles abrasion test is used to check the hardness of the aggregates.

Procedure for Los Angeles Abrasion test 

• The apparatus consists of a hollow steel drum where internal diameter is about 28 inches.
• Weight of the drum should be 5 kg to 10 kg.
• The drum is supported on a shaft.
• Then put a specified number of steel spheres in the drum.
• The drum is then rotated by some mechanical means.
• Speed of rotation should be 32 to 33 rounds per minute for a specific time.
• At the end, check that how much material is converted into powder.
• Take this material out of the machine.
• Sieve the material from #12 US Sieve.

Los Angeles abrasion value will be
L.A.A.V= (Fines/Sample)x100

• Higher the Los Angeles abrasion value, more weaker will be the material.
• Lower value shows that the aggregates are stronger.

Standard Values

• By AASHTO for base and sub base materials, L.A.A.V should not be more than 40%.
• By other agencies, L.A.A.V should not be greater than 50%.
• For wearing surface, standards are much more strict, because wearing surface is directly contacted to the movement of vehicles.