A method for assessing bond performance of cement-based repair materials

A test method is proposed to assess bond performance of cement-based repair materials in this paper. A specimen of circular substrate concrete plate with a frustum hole in the center was designed firstly, then the repair material was cast into the hole in a certain height, and lastly, the bond performance was assessed by checking the bond appearance, and testing the permeability and bond strength of the interface. Portland cement (PC), sulphoaluminate cement (SAC) and magnesium phosphate cement (MPC) mortars were used as repair materials to assess the bond performance by means of proposed method and the existing bending method. The results show that for PC and SAC mortars, a lot of thick cracks occurred on the interface due to the high shrinkage, while no crack was found in MPC mortar with lower shrinkage when proposed method used. For PC and SAC mortars, proposed method obtained lower bond strength than the bending method, which did not reflect the shrinkage of repair materials on the interface. It can be concluded that proposed method is suitable for assessing the performance of cement-based materials because it can measure the effect of repair material shrinkage on the bond of interface.