This standard outlines the laboratory test method for determining the aggregate impact value (AIV) of soft coarse aggregates. The AIV is a measure of an aggregate's resistance to sudden shock or impact, which is a critical property for materials used in road construction and pavement layers.
Method of test for determining aggregate impact value of soft coarse aggregates
Quick Reference Values
Test Hammer Weight13.5 to 14.0 kg
Hammer Drop Height380 ± 5 mm
Number of Blows15
Test Sample Sieve Fraction (Passing)12.5 mm
Test Sample Sieve Fraction (Retained)10 mm
Cylinder Internal Diameter102 mm
Final Crushed Material Sieve2.36 mm
Key Formulas
Aggregate Impact Value (%) = (W2 / W1) x 100; where W1 is the initial weight of the sample and W2 is the weight of material passing the 2.36-mm IS Sieve.
Practical Notes
This test is specifically intended for 'soft' aggregates. For general-purpose coarse aggregates, the procedure in IS 2386 (Part 4) should be followed.
Ensure the aggregate sample is oven-dried and brought to room temperature before testing to ensure accurate and repeatable results.
The test result is an empirical value; a higher AIV indicates a weaker aggregate with lower resistance to impact.