Molecular structure change and anti-aging performance of WFO-CR composite modified asphalts

Abstract

In order to use the solid and liquid waste resources to improve performances of base asphalt, waste frying oil (WFO) and crumb rubber (CR) are used to modify the asphalt to obtain the sustainable pavement material. The molecular structures and the performances of the modified asphalts with different amounts of WFO and CR are analyzed by conventional asphalt methods, short-term aging test and Fourier transform infrared spectroscopy (FT-IR). The results indicate that the retained penetration ratio (RPR), the softening point increment (SPI) and retained ductility ratio (RDR) indexes of modified asphalts with different amounts of WFO-CR composite are better than those of the base asphalt after short-term aging test. WFO and CR can improve anti-aging performance. Moreover, FT-IR results show that the absorption peaks at 814 cm^-1 and 720 cm^-1, which represent the alkenyl or benzene ring CC in WFO-CR composite modified asphalt after short-term aging, increase obviously. Both the carbonyl absorption peak and the sulfoxide absorption peak are improved for modified asphalts with different amounts of WFO-CR composite. The quantitative analysis shows that the carbonyl and sulfoxide indices of the modified asphalt reach the lowest values with 5.0% WFO and 20.0% CR, which are 36.02% and 32.04% lower than those of the base asphalt, respectively.