Los Angeles testing machine is used to conduct A. Abrasion test B. Impact test C. Attrition test D. Crushing strength test

The correct answer is: A. Abrasion test.

The Los Angeles Abrasion Test is a standard test method for determining the resistance of aggregates to degradation by abrasion. The test is conducted by rotating a drum filled with aggregates and steel balls. The aggregates are subjected to abrasion as the drum rotates. The amount of material lost by abrasion is then determined.

The Los Angeles Abrasion Test is used to evaluate the suitability of aggregates for use in concrete and asphalt pavements. The test results can be used to determine the durability of aggregates and to select aggregates that are resistant to abrasion.

The other options are incorrect because:

• Option B, Impact test, is a test to determine the resistance of materials to impact loading.
• Option C, Attrition test, is a test to determine the resistance of materials to wear by attrition.
• Option D, Crushing strength test, is a test to determine the compressive strength of materials.