Study of the modification mechanism and high-temperature rheological properties of OMMT/SBS-modified asphalt

Qiang Yi¹Zhenghao Zhang²Shengrui Tan³Chunhong Peng³Hongliu Rong^3*

• ¹Guangxi jiaotou technology co., ltd, Nanning, China
• ²Guangxi special geology highway safety technology innovation center, Nanning, China
• ³Guangxi University, Nanning, China

Adding nano-clay to asphalt binder has been shown to significantly improve its high-temperature performance. This study systematically investigates the effects of different organic montmorillonite (OMMT-F and OMMT-C) contents on the physical and high-temperature properties of styrene-butadiene-styrene (SBS) modified asphalt and clarifies the modification mechanism of OMMT-modified asphalt. The physical properties of the modified asphalt were evaluated using three testing methods: fluorescence microscope analysis (FM), rheological tests (DSR), infrared spectroscopy (FTIR), and atomic force microscopy (AFM), with the modification mechanism examined from a microscopic perspective. The results show that when the OMMT content is below 3%, the penetration and ductility of SBS modified asphalt are not significantly reduced. However, at 5% OMMT-F content, the penetration and ductility decrease by 12.5% and 33.4%, respectively, compared to OMMT-C, and the reduction increases with higher content. Compared to the original asphalt, the softening point increases as the OMMT content rises. FM analysis reveals that OMMT enhances the agglomeration of asphaltene in asphalt, thereby improving its high-temperature stability, with the best effect observed at 3% OMMT content. DSR testing shows that the rutting factor of modified asphalt increases progressively with OMMT content. Specifically, at 5% OMMT content and a temperature of 82°C, the rutting factor increases by 70% and 30%, respectively. FTIR analysis confirms that the modification of asphalt by OMMT is primarily a physical modification. AFM analysis shows that OMMT induces a honeycomb structure on the asphalt surface, which further enhances its high-temperature stability. This study compares the effects of two different OMMT types on asphalt from a microscopic perspective and provides a comprehensive analysis of both construction performance and microscopic surface characteristics, offering valuable insights into the improvement of SBS modified asphalt through OMMT modification. The findings have both significant research value and practical implications.