The sulfate soundness test has been used for many years for evaluating the physical suitability of fine aggregate. This test suffersfrom poor within-laboratory and multilaboratory precision; it is a time-consuming and expensive test. The work described here was an evaluation of alternative tests for measuring soundness of fine aggregate. The tests studied were the attrition test and a modified version of the french micro-deval test usually used for coarse aggregate. The micro-deval test was found to have a significant correlation with magnesium sulfate soundness loss and water absorption of fine aggregate. Unlike the attrition test, the micro-deval test is relativelyinsensitive to the gradation of the sand being tested and has excellent precision. The test is conducted by placing 500 g of water-saturated sand in a ball mill with 1250 g of 9.5-Mm steel balls and 750 ml of water. The mill is rotated at 100 rpm for 15 min. The aggregate is washed over a 75-microm sieve and the loss is calculated as a mass percent of the original oven-dry weight. The test may be completed in less than 48 hr. Aggregates that give more than 25% loss are judged to be marginal for use in portland cement concrete and asphaltic concrete. The ontario ministry of transportation has adopted the micro-deval test for measuring the quality of fine aggregate for concrete and asphalt. This paper appears in transportation research record no. 1301, Factors affecting properties and performance of pavements and bridges 1991.
Samenvatting