Effects of warm-mix asphalt technologies and modifiers on pavement performance of recycled asphalt binders

• Published in: Journal of cleaner production Vol. 282; p. 125435
• Main Authors: Li, Qiang, Sun, Guangxu, Lu, Yang, Meng, Yuanpeng, Luo, Sang, Gao, Lei
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2021
• Subjects: Aging simulation; Crumb rubber; Microstructure morphology; Pavement performance; SBR latex; Warm-mix recycling; SBR latex; Pavement performance; Warm-mix recycling; Microstructure morphology; Aging simulation; Crumb rubber
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2020.125435

The application of warm-mix recycling technology has been paid increasing attention because it not only increases the utilization ratio of reclaimed asphalt pavement (RAP) but also benefits environmental sustainability, which contributes to the reduction of greenhouse gas (GHG) emission and the preservation of natural raw materials. In this study, five recycling plans were designed with two types of warm mix asphalt (WMA) technologies along with two types of modifiers. Comprehensive characterization of recycled binders was performed to investigate the linear viscoelasticity, rutting resistance, and resistances to fatigue and low-temperature cracks of different recycled asphalt binders prepared by warm-mixing. The Fourier translation infrared spectroscopy test (FTIR) and environmental scanning electron microscopy (ESEM) was used to investigate the aging mechanism and the microstructure morphologies of recycled binders, respectively. It is observed that the multi-stress creep recovery test evaluates the resistance to rutting of polymer-modified binders more accurately under higher stresses. The use of the Sasobit WMA additive in recycled binders significantly improves the rutting resistance. However, it also leads to some negative effects on resistances to fatigue and low-temperature cracks. In contrast, the Evotherm WMA additive contributes to a drastic improvement in the low-temperature characteristic while a reduction in high-temperature performance. The addition of styrene-butadiene-rubber (SBR) latex significantly increases the resistance to rutting and slightly modifies the resistance to fatigue crack. The warm-mix recycled binder with crumb rubber powder (CRP) exhibits the best comprehensive performance, which is close to or even improved by comparing it with that of the original styrene-butadiene-styrene (SBS)-modified binder. The added SBR latex or CRP in warm-mix recycled binders shows a minor influence on the aging resistance. The suitable modifiers are recommended to be utilized to compensate for the loss of pavement performance caused by the use of WMA technologies and RAP. •Different types of pavement performance were evaluated for warm-mix recycled asphalt binders.•Effects of warm-mix asphalt technologies and modifiers were investigated for recycled asphalt binders.•The aging mechanism and microstructure morphologies of warm-mix recycled asphalt binders were discovered.