Evaluation of Natural Sands Used in Asphalt Mixtures

摘要

Five tests for sands were studied to determine if they could distinguish goodperforming natural sands from poor performing natural sands when used in asphalt mixtures: National Aggregate Association (NAA) Method A, direct shear, American Society for Testing Materials (ASTM) Method D 3398, Michigan Department of Transportation Method MTM 118-90, and a flow rate method. Performance was based on the effects of the sands on pavement rutting. The best methods for predicting how the sands would perform in pavements were the flow rate method, ASTM Method D 3398, and NAA Method A. The flow rate method is the easiest method to perform followed closely by the NAA method. ASTM Method D 3398 is very time consuming. The combined effects of shape, texture, gradation, and quantity of sand on the susceptibility of an asphalt mixture to rutting was evaluated using the U. S. Corps of Engineer's Gyratory Testing Machine (GTM), the Georgia Loaded Wheel Tester (GLWT), and the French Laboratoires des Ponts et Chaussees (LPC) Pavement Rutting Tester.