This part of IS 2386 outlines the test methods for evaluating the mechanical properties of concrete aggregates. It provides standard procedures for determining the aggregate crushing value, impact value, ten percent fines value, abrasion value, and polished stone value to ensure suitability for structural and pavement use.
Covers methods for determining mechanical properties like crushing strength, abrasion resistance, and impact value of aggregates.
Quick Reference Values
standard sample grading for ACV and AIVPassing 12.5 mm and retained on 10 mm IS Sieve
load applied in ACV test40 tonnes
rate of loading in ACV4 tonnes per minute (total 10 minutes)
impact value hammer weight13.75 to 14.25 kg
impact value drop height380 ± 5 mm
impact value blows15 blows
los angeles machine speed30 to 33 rev/min
sieve size for fines measurement in ACV and AIV2.36 mm
Key Formulas
Aggregate Crushing Value (ACV) = (B / A) * 100 — where B is weight passing 2.36mm sieve, A is total weight of sample
Aggregate Impact Value (AIV) = (B / A) * 100 — where B is weight passing 2.36mm sieve
Los Angeles Abrasion Value = (B / A) * 100 — where B is weight passing 1.70mm IS Sieve
Practical Notes
Ensure the test sample is oven-dried (100-110°C) for up to 4 hours before testing to avoid erroneous weights due to moisture.
The 10 percent fines value test is highly recommended over the aggregate crushing value for non-standard, weaker aggregates.
During the Los Angeles abrasion test, carefully select the abrasive charge (number of steel spheres) depending on the grading of the test sample as specified in Table 3.