Concrete-to-concrete bond strength: influence of an epoxy-based bonding agent on a roughened substrate surface

摘要

An experimental study was performed to evaluate the bond strength between two concrete layers, using different techniques for increasing the roughness of the substrate surface and a commercial epoxy-based bonding agent. A total of 40 slant shear half specimens and 40 pull-off half specimens first had the substrate surface prepared by wire-brushing, sand-blasting, chipping with a light jackhammer, or were left as-cast against steel formwork. Three months later, the bonding agent was applied and the new concrete was added. Pull-off tests and slant shear tests were performed to evaluate the bond strength in tension and in shear. Analysis of the results indicates that the application of an epoxy-based bonding agent does not improve the bond strength since the adopted method for surface preparation adequately increases its roughness.