Performance Evaluation of Asphalt Binder using Waste Pet and RAP

Abstract

Roads are considered as the backbone in the economy of Pakistan as it dominates over the other two systems of transport i.e. rail transport and the air transportation. However due to heavy expenditure involved in expansion of projects and lack of resources even for regular and routine maintenance of existing network, recycling is only the best possible solution. In a recent survey, Pakistan has got the highest mismanaged plastic wastes in the region of South Asia and produces 87000 tons of solid waste per day. Waste is also produced in the form of Reclaimed Asphalt Pavement (RAP) from the road construction industries. So, in this study, an effort is made towards the study of use of Reclaimed Asphalt Pavement and waste PET obtained from waste drinking plastic bottles as a partial replacement of asphalt use in the construction of asphaltic pavements. To do so, waste plastic bottles (PET) were collected, cleaned and shredded to a size less than 0.5mm, then they were mixed in percentages (2%,3%,5%,7%,9%by weight of virgin bitumen) at a temperature of 250°C with high speed shear mixer at 170rpm and physical tested in unaged and aged conditions to find the optimum dosage of binder. Four different percentages (10%,20%, 30% and 40%) of RAP was blended with (optimum dosage of 5%) of waste PET modified binder by means of a high-shear mixer, and then it was aged in the laboratory following a Rolling Thin Film Oven Test (RTFO) and a pressure aging vessel (PAV) machine. Penetration, Ring and Ball test, ductility and Rotational viscosity tests were performed before and after short-term aging and long-term aging respectively. The chemical and morphological changes were observed using FTIR and SEM i.e. Fourier Transformed Infrared Microscopy and Scanning of Electron Microscopy. Results indicated improvements in the modified asphalt physical properties and then modified asphalt added with optimum dosage of modifier along with different concentrations of RAP binder even after the process of aging. Viscosity aging index was decreased which indicates that Waste-PETMB with RAP binder has better anti-aging property. Decrease in the index of sulfoxide and carbonyl reflects good resistance against oxidation of the modified asphalt samples. Morphological analysis also proved their better compatibility with asphalt binder. Keywords: Reclaimed Asphalt Pavement(RAP),Viscosity ,PET, environment, aging, modified asphalt, Waste-PET MB