Enhancing Effect of Waste Engine Oil Bottom Incorporation on the Performance of CR+SBS Modified Bitumen: A Sustainable and Environmentally-Friendly Solution for Wastes

Abstract

Waste engine oil bottom (WEOB) is a hazardous waste whose effect as an additive to CR+SBS modified asphalt is rarely studied. In this study, the CR+SBS asphalt binder was modified with WEOB in different concentrations (3, 6, and 9 wt%). The GC–MS and FTIR were performed to evaluate the chemical compositions of WEOB and WEOBCR+SBS asphalt. The results showed that the main constituents of WEOB were similar to the functional groups of asphalt, along with maleic anhydride (MAH). Pavement performance-related rheological tests such as RV, temperature sweep (TS), FS, MSCR, and BBR were carried out. Results show that WEOBCR+SBS-6 exhibited the best high- and low-temperature property, followed by CR+SBS-3 and CR+SBS-9. Fluorescence microscope (FM) test, bar thin layer chromatograph (BTLC) test, FTIR, and AFM tests were carried out to evaluate the micro-morphologies and modification mechanism. The analysis revealed increased trends in resin fraction as opposed to asphaltene fraction with the increase of WEOB content. FTIR analysis revealed that the amide groups in WEOBCR+SBS asphalt bonded to the free radicals of CR. Moreover, a modification mechanism was elaborated. WEOB strengthens the cross-linked structure of CR+SBS polymers, reacting with SBS to graft onto MAH-g-SBS, and the free radical of CR interacts with the amide group in WEOB to form a bond. In addition, the content of lightweight components and surface roughness of SBS specimens were in good correlation, which contributed to the rutting resistance and adhesion and self-healing performance.

Application of Atomic Force Microscopy as Advanced Asphalt Testing Technology: A Comprehensive Review

“…From a microscopic point of view, WEOB promotes the polarity of SBS and forms the grafted product MAH-g-SBS with asphalt, which inhibits the thermal movement of molecules and improves the high temperature rutting resistance or elasticity, and the low temperature fatigue cracking resistance of asphalt. WEOB can also promote the development of a SBS network structure and improve the swelling properties and compatibility of asphalt [ 97 , 98 , 99 ].…”

“…For the modified asphalt mixture of CR and SBS, some experts and scholars have studied the influence of their composition and rheological properties on the modification mechanism. It was found that the free radicals of CR interact with the amide groups in WEOB to form a semi-continuous phase [ 99 ].…”

Modified Bitumen Materials from Kazakhstani Oilfield

“…Today, the modification of bitumen with polymers is recognized as a necessary technological method for obtaining highly efficient road construction materials based on this main organic binder [9]. To achieve this goal, a lot of research have been conducted [10][11][12][13][14][15][16]. The first mention of the use of polymers (natural rubber) to improve the properties of bitumen dates back to the last century [17].…”