Performance Evaluation of High-Density Polyethylene (HDPE) Modified Asphalt Concrete Mixtures

Abstract

The Pakistan’s road network has been continuously deteriorating due to the ongoing rise in traffic volume, increased loads and the insufficient level of maintenance brought on by a lack of funding. In the wake of the rise in usage, the modification of the bituminous binder with polymer additives has been studied in a number of nations throughout the world and in practice over the last four decades. The use of polyethylene material as a bitumen modifier has received a great boost due to its high tensile strength, impact resistance and melting temperature. This study was designed to examine the potential of enhancing the performance characteristics of asphalt mixtures using High-Density Polyethylene (HDPE) as a bitumen modifier in hot mix asphalt concrete (HMA) to focus three of the major distresses associated to flexible pavements such as fatigue cracking, moisture susceptibility and rutting resistance. The Marshall mix design was used first to determine the optimum binder content and then further to test the modified mixture properties. HDPE was blended in four varying proportions of 2.5%, 5.0%, 7.5% and 10.0% by the weight of bitumen and specimens were subjected to performance tests such as Tensile Strength Ratio (TSR), Resilient Modulus (MR) and Indirect Tensile Fatigue Tests (ITFT).The study finding conclude that adding High Density Polyethylene (HDPE) to asphalt concrete mixtures substantially improves the properties of the hot mix asphalt. The inclusion of 2.5% HDPE in the HMA has improved the stiffness response by almost 130.47%, the fatigue life enhanced by 642.0% and similarly the moisture resistance increased 17.81% in comparison to conventional mixes. Moreover, the behaviour of the specimens modified with higher polymer contents 5% and 7.5 % remains close to the optimum modifier content which was found to be 2.5% as it showed the best results among all polymer proportions. For validation of performance test results, a statistical analysis of one-way ANOVA with Tukey analysis and correlation was carried out and the analysis confirms the results drawn by this study.