Utilization of Waste Polythene Bags (LDPE) as Asphalt Binder Modifier in Asphalt Mix

Abstract

Modern transportation infrastructure is nowadays very important for everyday life of social beings. The traffic load placed on present pavements are notably severe than load in the past. Agencies are making effort in every possible way to strengthen the pavements and improve the service life of pavements. Polythene bags are regularly and extensively used around the globe for carrying shopping and household items. Disposal of these bags is a great problem. These bags are being burned or dumped on certain sites that create air and soil pollution producing dioxins which are quite injurious for health of human beings. Pavement design is primarily based upon the selection and gradation of aggregates and optimum binder content. Pavement over time get damaged by rutting and entrapped moisture. Therefore, it is needed to have such design which is cost effective and environmentally friendly. This research is based on performance evaluation of hot mix asphalt (HMA) by using different percentages of waste polythene bags (LDPE) as a replacement of OBC. NHA gradation B, PARCO grade 60/70 and LDPE from the dump yards of Islamabad were used in this study. Penetration, ductility and temperature testing was carried out of virgin bitumen and bitumen with different contents of LDPE (polythene bags flakes) i.e. 2%, 4%, 6% and 8% for determination of optimum modifier content. Determination of OBC, volumetric properties, flow and stability was done via Marshall testing. Using OBC and incorporating different LDPE contents as replacement of optimum bitumen content in asphalt mix, different samples were formed and tested for performance evaluation including rutting resistance and moisture susceptibility and compared with the performance testing results of HMA mixtures containing virgin bitumen only. It was observed that 4% of LDPE as a replacement of optimum bitumen content in HMA mix can be used (which was found to be optimum modifier content) and yielded better performance results than conventional mix as rutting resistance was improved about 20.86% and tensile strength ratio for moisture susceptibility evaluation was also above specified limit of 80%. Cost comparison was also carried out which showed 4% reduction in cost by utilizing 4% LDPE as replacement of binder