Evaluation of waste cooling oil and European Rock Asphalt modified asphalt with laboratory tests and economic cost comparison

The recycling of waste cooking oil (WCO) has attracted increasing interest while most research is connected to fuel and bio-lubricant production. The study aims to extend the possibility of applying WCO in asphalt modification to achieve environmental and economic benefits. Another nature-generated modifier, European rock asphalt (ERA), was also involved in compensating for the adverse effect of WCO on asphalt's high-temperature performance. Different ratios of WCO and ERA were adopted for preparing modified asphalt. The performance of asphalt, before or after aging, was evaluated with conventional tests (such as penetration, softening point, ductility, storage stability) and rheological tests, including Dynamic Shear Rheometer (DSR) test and Bending Beam Rheometer (BBR) test. The results indicated that WCO improved asphalt's resistance to low-temperature cracking by decreasing the creep strength and creep rate. The addition of ERA could counterbalance the detrimental effect of WCO on asphalt performance in high temperatures. Fourier transforms infrared spectroscopy (FTIR) was applied to investigate the modification mechanism, and no clear indication for a chemical reaction was observed. Modified asphalt at a proper ratio (4% WCO and 15% ERA for the investigated asphalt) can also present qualified storage stability, temperature susceptibility, and aging resistance. Finally, economic and environmental analyses were performed by comparing the cost and energy consumption of producing the performance grade level of asphalt in a traditional way or by this novel modification with WCO and ERA. The results indicated that modification of WCO and ERA could save more cost and cause less energy consumption.