Performance Evaluation of Modified Asphalt Concrete Mixes Containing Natural Sand

Abstract

The performance of Hot Mix Asphalt (HMA) mixtures is greatly affected by the properties of the aggregate characteristics. Although, the natural sand is readily available and less expensive as compared with crushed sand. The Standard Iraqi Specification for Roads and Bridge (SCRB, R/9) allowed using it with a ratio not exceed 25%. In this study, the performance of modified asphalt concrete mixes containing natural sand (desert sand and river sand ) and five replacement ratios for each one (0, 25, 50, 75 and 100% by weight of the sand passing sieve no. 8 and retained on sieve no 200) were evaluated. The performance of modified asphalt concrete mixes tensile strength, rutting is evaluated using indirect tensile test and wheel track test. The experimental work showed that the rutting depth for the modified specimens with polymers is lower than unmodified specimens at any percent of natural sand content and all test condition due to use of polymer modifier increased the stiffness of the binder at high pavement service temperature. The possibility of using natural sand specially desert sand with ratio exceed 25% by weight of the sand passing sieve no. 8 and retained on sieve no 200 for modified asphalt concrete mixes by polymers.