Evaluation of the performance of SBS/CR composite-modified deicing asphalt mixture prepared for ultra-thin wearing course

Deicing agents may compromise the performance of asphalt mixture. This article aims to study the feasibility of using styrene-butadiene-styrene (SBS)/crumb rubber (CR) modifier to prepare a deicing asphalt mixture with satisfactory performance for ultra-thin wearing course. High/low-temperature performance, water stability and deicing-related performances of the asphalt mixture were evaluated by conducting a series of laboratory tests from micro to macro level considering different incorporation rates of anti-freezing agent and SBS/CR modifier. The results find that SBS/CR modification enhances the high and low-temperature properties of the binder, and optimal incorporation ratios are 2% and 16%, respectively. The addition of anti-freezing agents as the filling material improves the high-temperature performance of the mortar, but negatively affects low-temperature performance. For asphalt mixtures, anti-freezing agents can enhance high-temperature performance by up to 56%, with only a minor impact on anti-sliding properties. However, they harm the low-temperature performance and water stability. A recommended maximum replacement ratio of 80% achieves satisfactory results in dynamic stability (11,053 times/mm), flexural strength (8.41 MPa), tensile strain (3011.08E⁻⁶), Marshall stability (9.61 MPa), Marshall residual stability ratio (81.28%), and free-thaw splitting ratio (80.30%), meeting the engineering standards. An Anti-freezing agent replacement ratio from 20% to 100% correlates linearly with a snow-melting rate of 16.3%− 96.8% and a deicing rate of 9.4%− 57.0%. The conductivity of soaking solution has been identified as a valuable indicator for predicting the asphalt functionality. This research can provide valuable insights into the mixture design and facilitate the practical implementation of this innovative functional material.