Drying shrinkage crack simulation and meso-scale model of concrete repair systems

摘要

Repairing materials and interfacial bonding quality are the two crucial factors that affect the shrinkage performance of concrete repair systems. The objective of this paper is to provide a fine meso-scale modelling method of concrete repair systems and to get a better understanding of shrinkage cracks propagation mechanism due to the influence of overlay materials, interface roughness and bonding strength. Through the laser scanning test and different algorithms, e.g. random cutting and random midpoint interpolation algorithm, geometry models of the 2D actual aggregate and rough interfaces with different fractal dimensions were generated. Besides, zero-thickness cohesive elements were inserted in mesh as the reserved path for cracks by modifying the inp file of ABAQUS. The validity of the model was verified by comparing with LI's experiment. Results of the simulation suggested that the final length of surface cracks and interface debonding depended on the overall shrinkage of the repair system and surface cracks mainly occurred in high bonding strength cases; aggregate nearby the interface caused the initial damage at low bonding strength interface, leading to the "stepped" debonding with time; The rough interface was more difficult to debond because it required more fracture energy and local shear stress was converted into compressive stress to prevent the development of debonding. (C) 2020 Elsevier Ltd. All rights reserved.