Research on Preparation Technology of Brittle-resistant Asphalt Mixture Based on Wet-Dry Combined Modification Processes

Abstract

This study aims to reduce the brittle point temperature of asphalt binders and improve the low-temperature mechanical properties of mixtures by developing a brittle-resistant asphalt mixture preparation technology for use in cold regions. The SBS wet-modified asphalt was combined with the melted star-shaped SBS modifier through a dry method. During mixing and transportation, the high-temperature effect helped form a secondary cross-linking effect with part of the original SBS-modified asphalt. The rest was evenly dispersed in the form of tough fillers, effectively avoiding the segregation and high viscosity issues caused by the conventional high-dosage wet-modified SBS asphalt. Tests were conducted on the brittle point temperature of asphalt binders, oil–aggregate interface adhesion grade, high- and low-temperature rheological properties of asphalt binders and the high- and low-temperature performances of the mixture to analyse the scientific nature of the developed preparation technology. Results show that compared with the conventional wet-modified SBS asphalt, the brittle-resistant SBS-modified asphalt prepared based on the wet–dry method has a reduced brittle point temperature by nearly 6.6°C, maintains an adhesion grade of 5 at the oil-aggregate interface. Moreover, the m value increases by approximately 1.3 times, the low-temperature bending strain of the mixture increases by approximately 70%, and the low-temperature bending strength is enhanced by approximately 60%. These results demonstrate that the proposed brittle-resistant SBS-modified asphalt preparation technology significantly improves the low-temperature performance of the mixture whilst ensuring mixing quality, which is crucial for enhancing the service performance of asphalt pavements in cold regions.