Study on SBS modifier of bio-oil/sulfur compound under dry modification mode

Abstract

To solve the problem of poor modification effect caused by insufficient swelling of SBS modifier in asphalt mixture under dry modification mode, the crosslinking reaction among bio-oil, sulfur, and SBS was used to prepare an efficient dry modifier to improve the road performance of dry modified asphalt mixture. At the micro level, the molecular models of asphalt, mineral, and compound SBS modifier were established. The basic properties of the compound-modified asphalt and the interaction between the compound-modified asphalt and mineral were predicted by four indexes, namely, microviscosity, relative distribution concentration, mean square displacement, and adhesion work. Macroscopically, the compound modifier was prepared by using bio-oil, sulfur, and SBS, and the reaction time was determined. The modification effect of the compound dry modifier was verified by a basic performance test of the asphalt and asphalt mixture. On the micro level, bio-oil/sulfur compound matched the SBS molecules in the asphalt model after determining that microscopic viscosity was higher than that in the common SBS model. The complex model matched the SBS asphalt in ore material on the surface in terms of the molecular diffusion rate, and adhesion effect also improved the SBS model in terms of predicting whether the complex matches dry process modification effect was superior to that of the common SBS modified agent. At the macro level, the reaction time of the compound modified agent was 30 min, and the prediction conclusion of molecular simulation was verified by the asphalt and asphalt mixture test. The penetration degree, softening point, ductility and aging indexes of the complex dry modified asphalt meet the standards of the wet modified asphalt in The Technical Specifications for Highway Asphalt Pavement Construction (JTG F40-2004). The indexes of high temperature rutting resistance, ultimate flexural strain and residual strength ratio of freezing-thawing splitting also reach the standard of wet-modified asphalt mixture.