Evaluation of Test Methods for Measuring the Bond Strength of Portland-Cement Based Repair Materials to Concrete

摘要

Three bond strength test methods were evaluated for screening and selecting repair materials used in overlaying and patching portland cement concrete. Bond strengths of three repair materials to base concrete were investigated using two uniaxial tensile bond strength test methods and a slant shear bond strength test method. The differing strengths of the repair materials caused different failure patterns, which had to be considered in the analyses of the failure stresses. Substantial differences in the failure stresses of the uniaxial tension and slant shear test methods were attributed to their different geometries and loading conditions. These differences emphasized the need to select test method(s) with geometry and loading conditions which are anticipated for the in-service repair material. For the two higher strength repair materials investigated, the relative precision (repeatability) of the slant shear and one of the uniaxial tensile test methods (pipe nipple grips) were comparable and relatively good (coefficient of variation values were about 5%).