Wetting model of rough solid surfaces and the effect of aggregate properties on epoxy resin binder-aggregate interface wetting.

• A new prediction model of wetting depth and wetting apparent contact angle of regular rough surface was established. • The roughness of aggregate surface, pore depth and pore resolution are important control parameters of wetting model. • Aggregate roughness, surface texture and aggregate lithology affect the wettability of epoxy resin binder on aggregate surface. • This paper provides some theoretical basis for exploring the overall wettability phenomenon and then revealing the essential laws of interfacial interactions. In order to study the effect of aggregate characteristics on the wetting of epoxy resin binder-aggregate interface, based on the Wenzel model and Cassie model, this paper established a new wetting model of the irregular rough surface. The model regularizes the rough solid surface and can calculate the wetting depth and apparent contact angle between different irregular rough solids and liquids. The texture parameters of aggregates, the surface tension of test liquids and the contact angles of different liquids-aggregates were tested by laser confocal tester and optical contact angle measuring instrument. It was found that the surface texture parameters of different aggregates were quite different. The relative error between the apparent contact angle calculated by the prediction model and the contact angle measured by the test was less than 15 %, indicating that the prediction model had excellent prediction effect. Through the analysis of the wetting model, it is found that the surface tension of the test liquid, the lithology of the solid aggregate, the surface roughness and the texture structure are the important control parameters affecting the wetting. The surface morphology of rough solid can be designed by changing the resolution k and depth H of micropores, so as to control the wettability of solid aggregate surface and epoxy resin aggregate. [ABSTRACT FROM AUTHOR]