Effects of asphalt binders on pavement mixtures using an optimal balance of desert sand

Abstract

Libya’s hot and arid desert regions create two serious constraints for Asphalt Concrete (AC); the temperature of the road surface can be as high as 70 °C and the humidity can be very low, resulting in premature AC deformation and cracking. This research demonstrates the effects of two different bitumen binders as variables against the control of a predetermined fine aggregate mix. The mixes are subject to several tests, including the Marshall, Superpave, Rutting Analyzer, and Complex modulus tests on AC. All samples were tested under simulated Libyan climatic conditions. These tests were conducted with an aggregate mix containing only 63% manufactured sand and 33% natural desert sand; this mix was used to test two asphalt binders, the widely-used B60/70 and the new PG70-10. As expected, all the tests performed on the B60/70 and PG70-10 mixes show that the PG70-10 mix is superior. Criteria for low-volume roads (LVRs) are met with the PG70-10 mix; this mix shows practical advantages for hot and dry regions where the use of locally available natural sand can result in substantial savings. For low-volume roads in remote areas, these findings are particularly important because economics do not justify the use of costlier higher-grade materials.