Interfacial adhesion mechanism between asphalt and aggregate with different lithology in acid–alkaline aqueous solutions

Strong adhesion at the asphalt–aggregate interface is vital for asphalt mixtures’ mechanical properties, but water damage can erode this adhesion, causing pavement distress. This study analyzed the effect of aggregate lithology (basalt, granite, and two limestones) on the water damage resistance of asphalt interfaces in acid–alkaline solutions using the boiling method, atomic force microscopy (AFM), and zeta potential measurements. AFM-measured interaction forces aligned with Derjaguin–Landau–Verwey–Overbeek theory. Acidic conditions showed higher adhesion forces and lower repulsive forces compared to alkaline conditions. Zeta potential values and long-range forces decreased with rising pH. Adhesion order in solution was limestone A > limestone B > basalt > granite. These findings reveal how aggregate lithology influences asphalt adhesion, aiding material selection for durable pavements.