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.
