Effects of waste engine oil on warm reclaimed asphalt mixture

Abstract

Depletion of natural resources and increase in energy consumption have led the pavement industry to actively explore innovative ways in creating sustainable infrastructure. In this context, the aim of this research was to investigate the modification of recycled binder and mixtures containing waste engine oil (WEO) with two types of warm asphalt additives; wax-based and oil-based. This study was divided into four phases. In the first phase, the WEO was blended with 0, 5, 10, 15 and 20 percent by weight of asphalt binder containing aged binder obtained from extraction and recovery of reclaimed asphalt pavement (RAP). The optimum WEO obtained from the first phase was blended with warm mix additives and tested in phase two. Two types of warm asphalt additives that had been applied were wax-based with dosages of 1%, 2%, and 3%, as well as oil-based with dosages of 0.3%, 0.4%, and 0.5% by weight of asphalt binder with WEO. These modified binders were subjected to storage stability, viscosity, rheology (temperature sweep, rutting resistance, and creep recovery), surface energy, as well as chemical characterization by using Fourier Transform Infrared Spectroscopy (FTIR) to determine the optimum additive content. In phase three, mechanical performance tests were performed by applying the optimum additive content obtained in phase two at compaction temperatures of 135°C, 125°C, and 115°C. The tests were resilient modulus, moisture resistance and rutting evaluation. In the final phase, the correlations between the properties of asphalt binder and the performance of the mixture had been determined by correlation coefficient analysis. The results show that 15% of WEO from various sources had been able to rejuvenate the aged binder to the base binder performance level. The optimum waxbased and oil-based additive contents were found to be 2% and 0.4%, respectively. The asphalt binder with wax-based additive improved the workability, hence displaying superior rutting resistance factor, better elastic response with reduced phase angle and reduction in aging level. Besides that, the mixture with wax-based additive exhibited higher resilient modulus, good moisture resistance, and acceptable lower rut depth, in comparison to other binders. The best compaction temperature was determined to be 135°C. In conclusion, the WEO emerged as a highly promising substance for modified binder with RAP and warm asphalt additive.