Los Angeles Abrasion Test Procedure

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METHOD OF TEST FOR ABRASION OF COARSE AGGREGATE BY USE OF THE LOS ANGELES MACHINE

S C O P E

This test method which is a modification of IRC Designation, is used to determine the resistance of coarse aggregate to impact in a rotating cylinder containing metallic spheres. This test is known as the Los Angeles Rattler Test.

. APPARATUS

1. Los Angeles Machine. The Los Angeles Abrasion Testing Machine shall conform to the essential design characteristics in Figure 1 and the narrative below. 2. Balance. The balance shall have a capacity of at least 5500 g and a sensi-tivity of 1 g or less. 3. Sieves. Standard 4.75 and 1.70-mm woven wire sieves shall conform to AASHTO Designation: M 92. These sieves should be at least 300 mm in diameter. 4. Abrasive Charge.

0 Each abrasive charge shall consist of a solid, steel sphere having a mass Test| Number| Mass of|
Specimen| of| Charge,|
Grading| Spheres| | in g| |
A . . . . . . . . . . . . .| . 12| 5000| ±| 25| B . . . . . . . . . . . . .| . 11| 4584| ±| 25| C . . . . . . . . . . . . .| . 8| 3330| ±| 20| D . . . . . . . . . . . . .| . 6| 2500| ±| 15|

TEST PROCEDURE

1. Place the test specimen and abrasive charge in the Los Angeles Abrasive Testing Machine and close the opening with the dust-tight cover.

2. Start the testing machine and allow to operate for the required number of revolutions.

3. When the testing machine has completed rotating the required number of revolutions, remove the cover and carefully empty the entire contents into a pan. Remove the abrasive charge from the pan.

4. Separate the test specimen on the 4.75-mm sieve, then sieve the passing 4.75-mm material on the 1.70-mm sieve. Combine the material retained on the 4.75 and 1.70-mm sieves. Weigh and record these values to the nearest 1 g.

5. If the mass of material retained on the 1.70-mm sieve was determined after 100...
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