ASTM C535-09 pdf free download.Standard Test Method for Resistance to Degradation of Large-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine.
1.1 This test method covers testing sizes of coarse aggregate larger than 19 mm (¾ in.) for resistance to degradation using the Los Angeles testing machine (Note 1).
4. Summary of Test Method
4.1 This test is a measure of degradation of mineral aggregates of standard gradings resulting from a combination of actions including abrasion or attrition, impact, and grinding in a rotating steel drum containing 12 steel spheres. As the drum rotates, a shelf plate picks up the sample and the steel spheres, carrying them around until they are dropped to the opposite side of the drum, creating an impact-crushing effect. The contents then roll within the drum with an abrading and grinding action until the shelf plate picks up the sample and the steel spheres, and the cycle is repeated. After the prescribed number of revolutions, the contents are removed from the drum and the aggregate portion is sieved to measure the degradation as percent loss.
5. Significance and Use
5.1 The test has been widely used as an indicator of the relative quality or competence of various sources of aggregate having similar mineral compositions. The results do not automatically permit valid comparisons to be made between sources distinctly different in origin, composition. or structure. Assign specification limits with extreme care in consideration of available aggregate types and their performance history in specific end uses.
6. Apparatus
6.1 The Los Angeles Machine shall conform to the require- men Is of Test Method C131.
6.1.1 The operation and maintenance of the machine shall he as prescribed in Test Method C131.
7. Sampling
7.1 Obtain the field sample in accordance with Practice D 75 and reduce to an adequate sample size in accordance with Practice C 702.
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 Table1 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 1 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 1000 revolutions (Note 3). Afier 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 liner portion on a 1.70-mm sieve in a manner conforming to Test Method C 136. Wash the material coarser than the 1.70-mm sieve and oven dry at 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.ASTM C535 pdf download.