Reaction mechanism and rheological properties of waste cooking oil pre-desulfurized crumb tire rubber/SBS composite modified asphalt. (8th March 2021)

• Record Type: Journal Article
• Authors: Zhao, Mengzhen; Dong, Ruikun
• Is Part Of: Construction & building materials. Volume 274(2021)
• Publication Date: 2021-03-08
• Subjects: Waste cooking oil -- Crumb tire rubber -- Styrene–butadiene-styrene block copolymer -- Composite modified asphalt -- Reaction mechanism -- Rheological property; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2020.122083
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: ODR/SBS composite modified asphalt is proposed to make up the loss of performance. Modification mechanism of the ODR composite modified asphalt is investigated. The effects of ODR, SBS and sulfur on rheological behaviors are evaluated. Sulfur can improve pavement performance of the ODR/SBS composite modified asphalt. Abstract: Waste cooking oil (WCO) is proved to be effective in desulfurization of crumb tire rubber (CTR), which can be considered as a sustainable desulfurization technology and an alternative way to solve the poor storage stability of asphalt rubber. However, WCO pre-desulfurized CTR (ODR) modified asphalt displays a compromised high-temperature performance, leading to a limited application of ODR in asphalt modification. In this study, ODR/styrene–butadiene-styrene (SBS) composite modified asphalt was developed to make up the loss of high-temperature performance. The reaction mechanism of ODR/SBS composite modified asphalts with and without sulfur was investigated via Fourier transform infrared spectroscopy (FTIR), gel permeation chromatograph (GPC) and fluorescence microscope (FM). Rheological tests were conducted to clarify the effects of ODR, SBS and sulfur on the rheological behavior of the modified asphalt. FTIR, GPC and FM results proved that crosslinking reaction occurred during the composite modification of ODR, SBS copolymer and base asphalt in the presence of sulfur with moderate content, forming a continuous and homogeneous microstructure with a significantly increased large molecular weight, which is less prone to produce phase segregation. The ODR composite modified asphalt with 3 wt% SBS and 0.4 wt% sulfur presents the best rutting resistance due to the increase of the elastic network structure and cracking resistance due to the presence of WCO and the released rubber chain. The above composite modified asphalt meets the standard traffic level at 76 °C and the specification at −34 according to the multiple stress creep recovery and bending beam rheometer tests.