Evaluation of the bond strength of a novel concrete for rapid patch repair of pavements

Patch repair is an important category in the repair or restoration of pavements. The effectiveness of the repair largely depends on the bond strength between the repair material and the concrete substrate. In the present work, surface roughness, bonding agents and curing age of the repair materials have been taken into consideration to evaluate the applicability and serviceability of a novel rapid repair material for concrete pavement. A three-factor and four-level orthogonal experiment was designed for systematic investigation. The bond strength of the combined specimens was measured using splitting tensile test and direct shear test. It is found that the splitting tensile strength varied from 1.21 MPa to 2.43 MPa and the direct shear strength varied from 2.84 MPa to 5.92 MPa and the bond strength has a good correlation with surface roughness and curing age. Different failure modes and the shear-slip characteristics were analyzed to understand the actual bond performance of combined specimens. It can be concluded that the slip distance of high surface roughness concrete was almost three times that of low surface roughness. In addition, the freeze-thaw cycle test of the combined specimen was conducted to validate the compatibility of the designed repair material with the concrete substrate. It is found that the he splitting tensile strength and direct shear strength of high surface roughness specimens reduced to 74.5% and 66.3% of its original bond strength after 100 times of freeze-thaw cycles, respectively. The rapid repair material studied in this study can act as a promising alternative for rapid patch repair of concrete pavements.