Shear fracture of longitudinally reinforced concrete beams under bending using Digital Image Correlation and FE simulations with concrete micro-structure based on X-ray micro-computed tomography images

The paper presents experimental and numerical investigations of the shear fracture in rectangular concrete beams longitudinally reinforced with steel or basalt bar under quasi-static three point bending. Shear fracture process zone formation and development on the surface of beams was investigated by Digital Image Correlation (DIC) whereas thorough analyses of 3D material micro-structure, air voids, width and curvature of shear cracking were carried out by X-ray micro-computed tomography (microCT). Moreover, the 2D shear fracture patterns in beams were numerically simulated with the finite element method (FEM) using isotropic coupled elasto-plastic-damage constitutive model for concrete enhanced by a characteristic length of micro-structure. Concrete meso-structure was modelled as a random heterogeneous four-phase material composed of aggregate particles, cement matrix, ITZ zones and air voids on the basis of X-ray micro-CT images. Experimental and numerical results revealed a satisfactory agreement regarding to the mechanism of failure, load-bearing capacity as well as cracking pattern. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

The paper presents experimental and numerical investigations of shear fracture in rectangular concrete beams reinforced with steel or basalt bar under quasi-static three point bending. Various techniques were used to study and analyze the shear fracture process zone and material micro-structure, air voids, and shear cracking characteristics. The results of experiments and numerical simulations showed satisfactory agreement in terms of failure mechanism, load-bearing capacity, and cracking patterns.