Assessing the effectiveness of using HDPE, PP and pet for surface course of flexible pavements

Abstract

Waste plastic disposal is a serious problem due to its non-bio-degradability. In order to overcome this issue, they should be reused in an effective way. This paper therefore focused on assessing the effects of addition of High- density polyethylene(HDPE), Propylene(PP) and Polyethylene terephthalate(PET) as partial replacement of bitumen used in surfacing of flexible pavements. In this study wet process was utilized, pure bitumen grade (60/70) modified bitumen with additive content of 4%,6%,8% and 10% were prepared and tested for rheological parameters. Using Marshall mix design, specimens were prepared at different bitumen contents (5%,5.5%,6%,6.5%7%) and the obtained OBC was 6% for conventional asphalt mix. Marshall tests were conducted on HMA samples with plastic content varied from 4%,6%,8% and 10% by weight of OBC and optimum plastic ratio was obtained as 6%,8% and 8% for HDPE, PP and PET respectively. The results from the Comparative study between conventional and modified HMA mixtures shows that addition of plastic improves the properties of HMA and bitumen. However, HMA with 8% PET showed better results of Marshall stability, volumetric properties, and tensile strength indicating better performance and durability of pavement. The use of PET in stone mastic asphalt helps mitigate the effects of plastic waste on to the environment as well as provide an alternative material to the road construction industry. The data parameters from the tests carried out on the materials was analysed using formulas input in Microsoft Excel.