Microscopic morphology and adhesion performance of SBS/OMMT modified asphalt under chloride salt erosion

Saline environment leads to the deterioration of asphalt adhesion behaviors, significantly impacting road surface lifespan. The objective of this study is to employ Styrene-Butadiene-Styrene (SBS) and organo-montmorillonite (OMMT) composite-modified asphalt to enhance its resistance to salt erosion. The microscopic structure, mechanical properties and nonlinear dynamical system stability of the SBS-OMMT modified asphalt before and after chloride salt erosion were assessed by atomic force microscopy (AFM). Various parameters including morphology, roughness, fractal dimension, height-height correlation function (HHCF), (Derjaguin-Muller-Toporov) DMT modulus, adhesion and Lyapunov exponent were comprehensively analyzed to assess the SBS-OMMT modified asphalt. Results indicate that with increasing OMMT content, the quantity of "bee structures" in the SBSOMMT modified asphalt increases while surface roughness and adhesion decrease, and the DMT modulus of the bee regions increases. Post chloride salt erosion, the "bee structures" in the SBS-OMMT modified asphalt become indistinct, peak-valley depth tends toward flatness, surface roughness and bee area DMT modulus increase, and adhesion decreases. Among these, the 5 % OMMT content in the SBS-OMMT modified asphalt exhibits the least variation. Fractal dimension reflects changes in the "bee structures" due to OMMT content and chloride salt erosion. HHCF provides information on roughness variation. SBS modified asphalt chloride salt erosion into a chaotic state, and OMMT can increase its stability. Research findings suggest that OMMT to a certain extent can resist the adverse effects of chloride salt on asphalt.