Large scale experimental study on bond behavior between polymer modified cement mortar layer and concrete

The effectiveness of concrete structures reinforced by the high strength steel wire mesh-polymer mortar depends on the bond-slip behavior of the interface between the polymer modified cement mortar layer (referred as mortar layer) and the concrete. The areas of the mortar layer tested in the previous studies are generally very small and the obtained conclusions are with limited applications. In this study, the experimental approach was used to analyze the slip behavior of the interface between the concrete block and a larger scale mortar layer. 30 concrete blocks retrofitted with mortar layers were fabricated and the single shear tests on these specimens were conducted. The applied shear loads, slip displacement between the concrete block and the mortar, as well as the strain of the mortar were monitored during tests. The experimental results exhibit the specimens have two representative failure types: debond with and without cracks. Then the bonding performance of the interface was systematically explored by analyzing the failure modes of the specimens and the mechanical property of the mortar. Meanwhile, the slip behavior of the interface influenced by the bond area, the thickness of the mortar layer, the mortar strength and the roughness of the interface were discussed. It was presented that the interface roughness treatment and increasing the mortar strength could significantly improve the behavior of the interface. (C) 2019 Elsevier Ltd. All rights reserved.