Characterization and Suitability Analysis of Recycled Waste Polymer Materials as Asphalt Mixtures in Hot Mix Asphalt.

Abstract

Today there is an increasing global trend to find sustainable, environmentally friendly and cost effective materials as an alternatives to the limited raw materials. Similarly the use of waste materials has been gaining popularity in the production of hot-mix asphalt (HMA). In this study, the potential possibility of recycled waste polymer materials like low density polyethylene (LDPE) as binder modifier and polyvinyl chloride pipe powder (PVC-PP) as filler in hot mix asphalt were evaluated based on the laboratory test experiments. The mixes were evaluated separately for each of the materials. Experimentally, a total of forty five Marshall Specimens were prepared with bitumen content of 4 to 6% at 0.5% increment and 5%, 5.5%, 6% of crushed stone dust as a control mix to determine optimum bitumen content and filler content. The determined optimum bitumen content was used to prepare Marshall Specimen with LDPE modifier from 0 to 10% at 2% increment and with PVC-PP filler from 0 to 100% at 25% increment. A total of thirty three (18 for LDPE and 15 for PVC-PP) specimens were prepared to evaluate the effects of the materials on Marshall Properties of hot mix asphalt, separately. Marshall Immersion test method was used to determine tensile strength ratio of modifier and filler to evaluate moisture susceptibility of the mix. All the mixes prepared with 5.43% optimum bitumen content and 5% filler content at different proportions of LDPE modifier and PVC-PP filler to meet Marshall Criteria for asphalt concrete wearing course. Maximum stability of 12.34kN was obtained at 8% of LDPE addition, while that of PVC-PP maximum stability 12.63kN was obtained at 50% replacement of PVC-PP. Marshall Immersion test resulted, tensile strength ratio of 60/70 PG binder and LDPE at its optimum content were 83.03 and 92.08 respectively, while that of crushed stone dust and partially replaced polyvinyl chloride pipe powder were 83.98 and 93.63 respectively. It was found that the addition of LDPE waste to an optimum content of 8% with the bitumen enhances Marshall Properties and 50% replacement of polyvinyl chloride pipe powder with 50% of crushed sand dust also enhances the mix’s properties. It is believed that the use of recycled LDPE and PVC-PP waste in hot mix asphalt within combination of plain bitumen and crushed sand dust is very useful to cost-effectiveness and in minimizing environmental problem due to waste disposal