Aggregate impact Value Toughness property Less than 10 Exception tough / Strong 10 to 20 Very tough / Strong 20 to 30 Good for pavement surface course Above 35 Weak for pavement surface.

The aggregates impact testing consists of a metal base and a cylindrical steel cup of internal. Diameter 102 mm and depth 50 mm in which the aggregate specimen is placed. A cylindrical metal hammer of weight 13.5 to 14 kg having a free fall Vertical guides.

Aggregates Specimen passing 12.5 mm sieve and retained on 10 mm sieve is filled in the cylindrical measures in three layers by temping each by 25 blows by the temping rod.

The sample is weighed and transferred from the measure to the cup of the aggregate impacts. Testing machine and compacted by temping 25 times. The hammer is raised to a height of 380 mm above the upper surface of the Aggregate in the cup and is allow to fall freely on the specimens after subjecting the test specimen to 15 blows, the crushed aggregate is sieved on 2.36 mm sieve. The aggregate impact value is expressed as the percentage of the fine passing 2.36 mm sieve formed in terms of the total weight of the sample.

ANS : Impact test on Aggregates: The aggregates impact testing consists of a metal base and a cylindrical steel cup of internal. Diameter 102 mm and depth 50 mm in which the aggregate specimen is placed. A cylindrical metal hammer of weight 13.5 to 14 kg having a free fall Vertical guides. Aggregates Specimen passing 12.5 mm sieve and retained on 10 mm sieve is filled in the cylindrical measures in three layers by temping each by 25 blows by the temping rod. The sample is weighed and transferred from the measure to the cup of the aggregate impacts. Testing machine and compacted by temping 25 times. The hammer is raised to a height of 380 mm above the upper surface of the Aggregate in the cup and is allow to fall freely on the specimens after subjecting the test specimen to 15 blows, the crushed aggregate is sieved on 2.36 mm sieve. The aggregate impact value is expressed as the percentage of the fine passing 2.36 mm sieve formed in terms of the total weight of the sample.