Aggregates - Abrasion Value

AIM
To determine the abrasion value of coarse aggregates as per

IS: 2386 (Part IV) - 1963. 


APPARATUS
LOS ANGLES MACHINE

  1. Los Angles abrasion testing machine
  2. IS Sieve of size - 1.7mm
  3. Abrasive charge - 12 nos. cast iron or steel spheres  approximately 48mm dia. and each weighing between 390 and 445g ensuring that the total weight of charge is 5000 + 25g
  4. Oven



PREPARATION OF SAMPLE
The test sample should consist of clean aggregates which has been dried in an oven at 105 to 110o C to a substantially constant weight and should conform to one of the gradings shown in the table below: 

PROCEDURE 

The test sample and the abrasive charge should be placed in the Los Angles abrasion testing machine and the machine rotated at  a speed of 20 to 33 revolutions/minute for 1000 revolutions. At the completion of the test, the material should be discharged and sieved through 1.70mm IS Sieve. 


REPORTING OF RESULTS

  1. The material coarser than 1.70mm IS Sieve should be washed, dried in an oven at a temperature of 100 to 110o C to a constant weight and weighed (Weight 'B').
  2. The proportion of loss between weight 'A' and weight 'B' of the test sample should be expressed as a percentage of the original weight of the test sample. This value should be reported as,

                                          A - B

Aggregate abrasion value = ———– x 100%
                                             A
A sample proforma for the record of the test results is given in Annexure-II.

Comments

Post a Comment