Shear bond assessment of UHTCC repair using push-out test

This investigation is aimed at assessing the shear bond strength between existing concrete and an ultra-high toughness cementitious composite (UHTCC). The main issues relevant to a push-out test are the type of interface treatment agent, the strength of the existing concrete, the substrate surface treatment, and the surface treatment of the precast UHTCC. An analysis of variance (ANOVA) is presented to evaluate the significant factors. In addition, mathematical models are built to estimate the shear bond strength. The results indicate that the primers and bonding agents can improve the interface bond, and the highest shear bond strength is achieved using a polymer-modified material. The strength of the existing concrete has a certain influence on the bond. A substrate surface treatment is also a vital factor, and has a strong effect on the shear bond strength. However, excessive mechanical action leads to interface damage. There are two bond planes for precast repair specimens, and it is imperative to maintain a good quality and consistent speed failure for both. ANOVA is an acceptable and effective way to determine the significance. The proposed models have high accuracy and satisfactory prediction capability. (C) 2017 Elsevier Ltd. All rights reserved.