To Perform Los Angeles Abrasion Test on Given Sample - Lab Report
(AASHTO DESIGNATION: T-96 | ASTM C 131)
The Los Angeles test is a measure of degradation of mineral aggregates of standard gradings resulting from a combination of actions including abrasion or attrition, impact, and grinding in a rotating steel drum containing a specified number of steel spheres. The Los Angeles (L.A.) abrasion test is a common test method used to indicate aggregate toughness and abrasion characteristics. Aggregate abrasion characteristics are important because the constituent aggregate in HMA must resist crushing, degradation and disintegration in order to produce a high quality HMA.
Principle of the Test:
To produce the abrasive action by use of standard steel balls which when mixed with the aggregate and rotated in a drum for specific number of revolution cause impact on aggregate. The %age wear due to rubbing with steel balls is determined and is known as abrasion value.
Prepare the sample by the portion of an aggregate sample retained on the 1.70 mm (No. 12) sieve and place in a large rotating drum that contains a shelf plate attached to the outer wall.
Procedure of the LA Abrasion Test:
Test Sample :
Sample shall be washed and oven-dried at a temperature of 105°C - 110°C and should conform to one of the grading in observation.
Test Adequacy / Suitability:
The L.A. Abrasion test is an empirical test; it is not directly related to field performance of aggregates. Field observations generally do not show a good relationship between L.A. abrasion values and field performance. L.A. abrasion loss is unable to predict field performance. Specifically, the test may not be satisfactory for some types of aggregates. Some aggregates, such as slag and some limestones, tend to have high LA. abrasion loss but perform adequately in the field. L.A. abrasion loss seems to be reasonable well correlated with dust formation during handling and HMA production in that aggregates with higher LA. abrasion loss values typically generate more of dust.
Uses & Significance of LA Abrasion Test :
Standard Test Methods are: