Experimental study of the interfacial bond strength between cementitious grout and normal concrete substrate

The interfacial bond strength between cementitious grout and normal concrete substrate was experimentally investigated by conducting slant shear tests and splitting tensile tests. The effects of concrete substrate strength, surface roughness, and type of cementitious grout on the bond strength of cementitious grout and normal concrete were discussed in detail. The results showed that, for composite specimens, the effects of concrete substrate strength on the slant shear bond strength were more obvious than those on the splitting tensile bond strength. Specifically, with an increase in the normal concrete substrate strength, the slant shear bond strength showed an increasing trend for composite specimens with a surface roughness of 0.25 mm, and it exhibited no significant trend for slant shear composite specimens with a lower surface roughness (0, 0.06, and 0.13 mm) and splitting tensile composite specimens. With an increase in surface roughness, the slant shear bond strength and splitting tensile bond strength presented different degrees of increase within a certain limit. In addition, a comparison of specimens with different types of cementitious grout indicated that the interfacial bond strength of specimens prepared using CGM-270 overlays was the highest. The relationship between slant shear strength and splitting tensile bond strength was analysed, and a linear correlation between the slant shear bond strength and splitting tensile bond strength was established. Thereafter, empirical models of the slant shear bond strength and splitting tensile bond strength between cementitious grout and normal concrete were proposed. (C) 2020 Elsevier Ltd. All rights reserved.