Preparation, Characterization, and Anti-Icing Properties of Sustained-Release Low-Freezing-Point Asphalt Mixture

Abstract

Pavements covered with snow and ice in winter will reduce antiskid performance, which may cause harm to road operation safety. In this study, an asphalt mixture containing a low-freezing-point additive (LFPA) was developed for pavement applications, and its antifreezing properties were evaluated experimentally. Eight kinds of porous materials including volcanic rock, fly ash, zeolite, diatomite, and modified diatomite were selected as carriers. The optimum salted carrier and surface modifier and the preparation conditions of LFPA were studied by conductivity test, rapid determination of chloride ion test, laser size distribution apparatus (LSDA), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The asphalt mixture containing LFPA by volume displacement method was prepared by the Marshall test, and its pavement performance and antifreezing properties were evaluated. The results showed that modified diatomite (ground for 10 min) exhibits high chloride adsorption capacity, and Span 60 (Sorbitan Monostearate) is the optimum surface modifier of the coated carrier. The ratio of surface modifier and carrier salt is 1∶5, and the modification temperature of surface modifier is 80°C. Moreover, when the mineral fillers in the styrene-butadiene-styrene (SBS) asphalt mixture are partially replaced by the LFPA, the rutting resistance increases at first and then decreases, and low-temperature stability and water stability decrease with increasing LFPA content. Finally, the deicing performance evaluation showed that the ice-melting ratio can be significantly improved by adding LFPA to the mixture. At a content value of sustained-release LFPA of 20%, the ice-melting ratio was maximized.