What is aggregate impact testing, and what are the specifications of the apparatus used in this testing?

Question

Accepted Answer

Aggregate impact testing is a method to determine the toughness of aggregates used in road construction.

It involves dropping a metal hammer on a sample of aggregate and measuring the amount of fragmentation.
The apparatus used in this testing includes an impact testing machine, a cylindrical measure, a tamping rod, and a balance.
The impact testing machine consists of a metal base, a vertical guide, and a hammer of weight 13.5 to 14 kg.
The cylindrical measure is filled with aggregate and tamped 25 times with the tamping rod.
The sample is then placed on the base of the impact testing machine and the hammer is allowed to fall freely.
The amount of fragmentation is measured by sieving the sample through a set of sieves.
The specifications for this testing are given in ASTM C131 and AASHTO T96 standards.

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