DETERMINATION OF LOS ANGELES ABRASION VALUE
(i) to determine the Los Angeles abrasion value.
(ii) to find the suitability of aggregates for use in road construction. APPARATUS:
The apparatus as per IS: 2386 (Part IV) – 1963 consists of: (i) Los Angeles Machine: It consists of a hollow steel cylinder, closed at both the ends with an internal diameter of 700 mm and length 500 mm and capable of rotating about its horizontal axis. A removable steel shaft projecting radially 88 mm into cylinder and extending full length (i.e.500 mm) is mounted firmly on the interior of cylinder. The shelf is placed at a distance 1250 mm minimum from the opening in the direction of rotation. (ii) Abrasive charge: Cast iron or steel balls, approximately 48mm in diameter and each weighing between 390 to 445g; six to twelve balls are required. (iii) Sieve: 1.70, 2.36,4.75,6.3,10,12.5,20,25,40,50,63,80 mm IS Sieves. (iv) Balance of capacity 5kg or 10kg
(v) Drying oven
(vi) Miscellaneous like tray
The aggregate used in surface course of the highway pavements are subjected to wearing due to movement of traffic. When vehicles move on the road, the soil particles present between the pneumatic tyres and road surface cause abrasion of road aggregates. The steel reamed wheels of animal driven vehicles also cause considerable abrasion of the road surface. Therefore, the road aggregates should be hard enough to resist abrasion. Resistance to abrasion of aggregate is determined in laboratory by Los Angeles test machine. The principle of Los Angeles abrasion test is to produce abrasive action by use of standard steel balls which when mixed with aggregates and rotated in a drum for specific number of revolutions also causes impact on aggregates. The percentage wear of the aggregates due to rubbing with steel balls is determined and is known as Los Angeles Abrasion Value. PROCEDURE:
The test sample consists of clean aggregates dried in oven at 105° – 110°C. The sample should...
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