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LOS ANGELES ABRASION VALUE TEST as per IS 2386 part iv
Apparatus - The apparatus shall consist of the following:
Los Angeles machine --- The Los Angeles abrasion testing machine,
conforming in all its essential characteristics to the design shown
shall be used. The machine shall consist of a hollow
steel cylinder, closed at both ends, having an inside diameter of
700 mm and an inside length of 500 mm.
b) Sieves - The I-70-mm IS Sieve.
Abrasive Charge-The abrasive charge shall consist of cast iron
spheres or steel spheres approximately 48 mm in. diameter and each weighi
between 390 and 445 g.
The abrasive charge, depending upon the grading
Procedure-
The test sample and the abrasive charge shall be placed in the
Los Angeles abrasion testing machine and the machine rotated at a speed of
20 to 33 rev/min. For gradings A, B, C and D, the machine shall be rotated
for 500 revolutions; for gradings E, F and G, it shall be rotated for 1 000
revolutions. completion of the test, the material shall be discharged from the machine and a preliminary separa tion of the sample made on a sieve coarser than the l-70-mm IS Sieve.
CALCUTIION :
Los Angeles abrasion value =Different in weight/Weight of Sample x 100
Example-
Weight of Sample =5000 gm
Weight after test(wash & oven Dry) = 4087 gm
Then: Abrasion value = (5000-4087)/5000X100
Abrasion value = 913/5000 x 100
Abrasion value = 18.26 %
Permissible limit are below 40 %
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