Engineering Performance and Sustainability Assessment of Warm-Mix SBS-Modified Asphalt Mixture with Foaming Technique

With the increasing consideration of sustainability in infrastructure materials, both modified asphalt and warm-mix asphalt have received remarkable attention. However, little is known about characteristics of warm-mix styrene-butadiene-styrene (SBS) modified asphalt with foaming technique (FWMA-SBS). The present study is dedicated to optimizing fabrication of the FWMA-SBS binder and investigating the performance of the foamed SBS-modified asphalt mixture. To achieve desirable foaming characteristics, the FWMA-SBS binder is produced at foaming temperature of 130°C, water content of 2.0%, and air pressure of 0.55 MPa. The production temperature of the FWMA-SBS mixture is significantly lowered by 20°C compared to traditional SBS-modified asphalt mixture. It has demonstrated that engineering performance of FWMA-SBS binder coincides with the mixture. The FWMA-SBS mixture features better low-temperature cracking resistance and fatigue performance, while it exhibits lower rutting resistance and similar moisture stability in comparison with a traditional SBS-modified asphalt mixture. The sustainability assessment verifies that compared to conventional SBS-modified asphalt mixture, the production of 1 ton of FWMA-SBS mixture leads to energy savings of 9.8%, cost reduction of $1.81, and less energy associated with CO2 by 9.8%. The research accomplishments promote the utilization of the foamed SBS-modified asphalt, realizing the pavement sustainability from principles to practices.