Properties of Interface Structure between Ultra-Thin White Topping and Old Concrete Pavement

Abstract

The research of this paper focused on bond characteristics of overlay-substrate interface in ultra-thin white topping(UTW), aim at ultra-thin concrete overlay on old concrete. Compressive and shear stress have been considered in the structural analysis and experimental research. Bonding behaviors of several surface pretreatments to old concrete have been investigated. A shear-peel test device has been developed to imitate brake-load of wheels at the plate boundary of UTW, and its analytical calculate principle have been discussed to simulate the mechanical theory of the shear peel test. Structural analysis and experimental research results indicate that various flaws are accumulated remarkably in the transition layer at overlay-substrate interface in UTW. Different surface pretreatments of the old concrete will influence on the bonding characteristics of overlay-substrate interface, chiseling treatment for interface has more contribution to working together with the new concrete, but interface adhesive agent enhances the coordination between the interface and the old concrete layer. The treatment combination of chiseling and brushing interface adhesive can effectively improve the strength of the weak interface transition layer. Shear-peel test results indicate that the interlocking influence generated by chiseling treatment is prior to brushing interface adhesive. It is necessary turn to account suitable measure to prevent ultra-thin concrete overlay peeling off from old concrete.