Which test measures aggregate toughness?

• A. Freeze-thaw resistance test.
• B. Water absorption test.
• C. Los Angeles Abrasion (LA Abrasion) test.
• D. Indirect tensile strength test.

Answer: (C)

Aggregate toughness means how well the material resists wear and crushing when subjected to the grinding and friction it would experience in traffic. The Los Angeles Abrasion test targets exactly this property. In the test, a sample of aggregate is placed in a steel drum with steel grinding balls and rotated for a specified number of revolutions. The pounding and grinding simulate the combined effects of impact and abrasion that pavement aggregates face in service. After the run, the material is cleaned and weighed, and the percent loss is reported. A smaller loss indicates tougher, more wear-resistant aggregate, which helps pavements stay intact longer under traffic.

Other tests measure different properties: freeze-thaw resistance examines durability under cycles of freezing and thawing rather than wear; water absorption assesses how much moisture the aggregate can take up (porosity), not its resistance to abrasion; and the indirect tensile strength test evaluates strength under tensile loading rather than resistance to surface wear.