ASTM C535:16 pdf free download – Standard Test Method for Resistance to Degradation of Large-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine.
7. Sampling
7.1 Obtain the field sample in accordance with Practice D75/D75M and reduce to an adequate sample size in accordance with Practice C702/C702M.
8. Test Sample Preparation
8.1 Wash the reduced sample and oven dry at 110 ± 5°C (230 ± 9°F) to substantially constant mass, separate into individual size fractions, and recombine to the grading of Table I most nearly corresponding to the range of sizes in the aggregate as furnished for the work. Record the mass of the sample prior to test to the nearest I g.
9. Procedure
9.1 Place the test sample and charge in the Los Angeles testing machine and rotate the machine at 30 to 33 r/min for l000 revolutions (Note 3. After the prescribed number of revolutions, discharge the material from the machine and make a preliminary separation of the sample on a sieve coarser than the 1.70-mm (No. 12) sieve. Sieve the finer portion on a l.70.rnm sieve in a manner conforming to Test Method Cl36Kl36M. Wash the material coarser than the l.70-rnni sieve and oven dry al 110 5°C (230 ± 9°F to substantially constant mass, and determine the mass to the nearest I g
9.1.1 If the aggregate is essentially free of adherent coatings and dust, the requirement for washing after the test is optional. However, in the case of referee testing, the washing procedure shall be performed. Elimination of washing after tes will seldom reduce the measured loss by more than about 0.2 % of the original sample mass.
Note 3—Valuable information concerning the uniformity of the sample under test may he obtained by determining the loss alter 200 revolutions. This loss should be detennined by diy sieving the mntieria1 on the l,70’nun (ro. 12) sieve without wahing. The raio of the loss aher 200 tcoluiions It) the loss alter l() revolutions should not greatly exceed 0.20 for material of uniform hardness. When this detennination 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 linal t00 resolutions required to complete the test.
10. Calculation
10.1 Calculate the loss Uhe difference between the original mass and the final mass of the test sample) as a percentage of thc original mass of the test sample (Note 4).
Note 4—1bc percent loss dcicnnincd by this method has no known COflsistCflt relationship to the percent loss for the same material when tcstcd by Tesi Method C131/C131M.
11. Report
11.1 Report the following information:
11.2 Identilication of the aggregate as to source, type, and nominal sue, 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. Prevision and Bias
12.1 Precision:
12.1.1 Single Operator Precision—The single-operator coefficient of variation has been found to be 3.7 %. Theretlwe. results of two properly conducted wsts by the same operator on the same material arc not expected to difkr by more than 10.4 f of their average.
Therefore. results of two different laboratories on identical samples of the same material are not espected to differ from each other by more than 18.1 k of their average.