Numerical Generation and Contact Analysis of Rough Surfaces in Concrete

Abstract

In concrete structures, opened cracks contribute significantly to the transfer of shear and normal stresses through the contact forces occurring between fractured surfaces. Such contact forces are due to protruding asperities, engaged by interlocking and friction. In this paper, the role played by roughness on shear resistance is investigated numerically. First, micro computed tomography and digital microscope measures of concrete surfaces are used to validate a novel numerical generator of realistic cracked concrete surfaces. Secondly, a contact solver based on the boundary integral approach allows an extremely fine description of typical cracked surface topologies. Roughness changes drastically the predictions, so that the shear resistance computed numerically matches the prior experimental results reported in the literature. The proposed model does not need any fitting procedure, making it a reliable and physically based method for predicting shear transfer phenomena in concrete. An empirical power-law predicting the shear resistance in concrete is a direct outcome, which accounts for micro-scale roughness and aggregate distribution.

Multiscale Modeling of Rough Contact Interfaceswith Trapped Compressive Liquid Pockets

“…Assuming the validity of Jonhson's hypothesis, the height profile can be substituted by the initial gap profile h, which is now acting as an effective rigid roughness profile to be pressed against a flat deformable surface. Such a strategy was already used in [20], and is illustrated in Figure 2. To account for the distinct material behaviors of both surfaces in contact, we calculate an equivalent Young's modulus E * , derived from Hertz contact theory [17], as follows:…”

Aggregate interlock in fractured concrete mesoscale models: a novel finite element modelling approach

“…This study provides guidance to develop a novel mesoscopic FE modelling method to investigate the aggregate interlock stresses when crack surfaces are subjected to mixed-mode crack kinematics. The mesoscopic nature of the FE model yields most realistic crack surfaces with less effort compared to the mathematically develop crack surfaces [17]. This study helps to understand the aggregate interlock mechanism and its influence on the amount of stress transfer between two crack surfaces under different crack kinematics.…”

Extension of dashpot model with elastoplastic deformation and rough surface in impact behavior

“…From the microscopic perspective, the engineering surface is composed of innumerable asperities [1,2] with multi-scales; hence, the surface roughness has a conspicuous influence on the impact behavior, fatigue, and vibration phenomena [3][4][5]. Actually, when the rough surfaces come into contact with each other, the squeeze and shear behaviors only happen in the interaction between the higher asperities rather than the entire surface [6].…”