5.1 The Micro-Deval abrasion test is a test of fine aggregate to determine abrasion loss in the presence of water and an abrasive charge. Many aggregates are more susceptible to abrasion when wet than dry, and the use of water in this test incorporates this reduction in resistance to degradation. The test results are helpful in evaluating the toughness/abrasion resistance of fine aggregate subject to abrasion when adequate information is not available from service records. This test is suitable for measuring the amount of weak, soft material such as shale or shaley carbonate in fine aggregate. Materials that give a low loss in this test are unlikely to exhibit significant degradation during handling, mixing or placing. There is a relationship between drying shrinkage of cement mortar and Micro-Deval abrasion loss of fine aggregate, with higher loss materials resulting in higher drying shrinkage. Descriptions of the development of the test and the relationship with other properties have been published.3^,4^,5

5.2 The Micro-Deval abrasion test on fine aggregate is useful for detecting changes in properties of aggregate produced from an aggregate source as part of a quality control or quality assurance process.

5.3 The Micro-Deval abrasion test on fine aggregate, in contrast to the version on coarse aggregate, has a significant correlation with the Magnesium Sulfate soundness loss of fine aggregate. The Micro-Deval test on fine aggregate has better precision than the sulfate soundness test, is quicker, and may be used in place of that test. Advice on specific values for selection of aggregate will be found in the appendix.