Multi-scale study on interfacial bond failure between normal concrete (NC) and ultra-high performance concrete (UHPC)

• Published in: Journal of Building Engineering Vol. 57; p. 104808
• Main Authors: Yu, Jiangjiang, Zhang, Boshan, Chen, Weizhen, Liu, Hang, Li, Heng
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2022
• Subjects: Damage characteristics; Debonding behavior; Multi-scale homogenization; NC-UHPC interface; Traction-separation law; Debonding behavior; Multi-scale homogenization; Damage characteristics; Traction-separation law; NC-UHPC interface
• ISSN: 2352-7102; 2352-7102
• DOI: 10.1016/j.jobe.2022.104808

It is a promising way to strengthen and repair the damaged normal concrete (NC) structure with ultra-high performance concrete (UHPC), and the interfacial performance between NC and UHPC is a critical issue. This paper aims to reveal the debonding failure performance between UHPC (repair material) and NC (substrate material) under tensile loading and shear loading. A multi-scale analysis method is established to simulate the mechanical behavior of the NC-UHPC interface, considering the complex interface geometry on the meso-scale. The failure of NC matrix is described by the elastic-plastic damage model in form of coupled gradient-enhanced damage evolution, the interface is represented by the cohesive zone model (CZM), and the UHPC is characterized by the second-order mean-field homogenization (MFH) method. After extracting the roughness characteristic parameters of the tested interfaces, the representative volume element (RVE) corresponding to the roughness is established, the load transfer and the debonding failure behavior are investigated, and the effective traction-separation law (TSL) is obtained. Finally, the tensile and the shear separation mechanisms of the NC-UHPC interface are revealed, and the effects of the roughness and strength of the interface on the macro shear and tensile strength are evaluated. Both the interface roughness and the substrate concrete strength have positive effects on the mechanical properties of the interface. •A multi-scale analysis method for debonding behavior of NC-UHPC interface is proposed.•A numerical homogenization scheme is applied to predict the NC-UHPC interface performance.•The failure mechanism of NC-UHPC interface under tensile and shear loads is revealed.