Aggregate Impact Value

A sample is subjected to 15 blows from a standard falling hammer in an impact-testing machine, then sieved on a 2.36 mm sieve. The percentage of material passing the sieve is the Aggregate Impact Value.

This test complements the crushing value test by assessing toughness under sudden impact rather than gradual load — a relevant distinction for aggregate used in road surfacing, where traffic applies dynamic rather than static loads.