ASTM C535:2009 pdf free download – Standard Test Method for Resistance to Degradation of Large-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine.
NOTE 3—Valuable information concerning the uniformity of the sample under test may be obtained by determining the loss after 200 revolutions. This loss should be determined by dry sieving the material on the I .70-mm (No. 12) sieve without washing. The ratio of the loss after 200 revolutions to the loss after 1000 revolutions should not greatly exceed 0.20 for material of uniform hardness. When this determination is made, take care to avoid losing any part of the sample; return the entire sample, including the dust of fracture, to the testing machine for the final 800 revolutions required to complete the test.
10. Calculation
10.1 Calculate the loss (the difference between the original mass and the final mass of the test sample) as a percentage of the original mass of the test sample (Note 4).
NOTE 4—The percent loss determined by this method has no known consistent relationship to the percent loss for the same material when tested by Test Method C 131.
11. Report
11.1 Report the following information:
11.2 Identification of the aggregate as to source, type, and nominal size, and
11.3 Grading designation from Table I used for the test, and
11.4 Loss by abrasion and impact of the sample expressed to the nearest I % by mass.
12. Precision
12.1 Repeatability—Based on four replicate tests by a single operator on one aggregate at a single laboratory using the same equipment, the average degradation (abrasion) loss, with a No. I grading was found to be 38.8 % and the standard deviation was 1.8 %
12.2 Bias—No statement is being made about the bias of this Test Method since there is no accepted reference material suitable for determining the bias of this procedure.
13. Keywords
13.1 abrasion: aggregate (coarse: large size): degradation; impact; Los Angeles machine.
X 1.1 The shelf of the Los Angeles machine is subject to severe surface wear and impact. With use, the working surface of the shelf is peened by the balls and tends to develop a ridge of metal parallel to and about 32 mm (11/4 in.) from the junction of the shelf and the inner surface of the cylinder. if the shelf is made from a section of rolled angle, not only may this ridge develop but the shelf itself may be bent longitudinally or transversely from its proper position.
The infuence on the test result of the ridge developed by peening of the working face of the shelf is not known. However, for uniform test conditions, it is recommended that the ridge be ground off if its height exceeds 0.1 in.(2 mm).