L. Bitencourt - Academia.edu (original) (raw)
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University of Engineering & Technology Lahore, Pakistan
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At the mesoscopic level, the fracture behaviour of high strength concrete (HSC) can differ signif... more At the mesoscopic level, the fracture behaviour of high strength concrete (HSC) can differ significantly from the conventional strength concrete since the coarse aggregate may be the weakest phase of the composite. In this way, the influence of coarse aggregate type, size, and distribution can affect all the macroscopic mechanical responses, such as the ultimate tensile strength and fracture energy. The present work proposes a concurrent two-scale (macro and mesoscale) approach for HSC, in which (i) a linear elastic model with homogenized elastic properties is used for the macroscale and (ii) a three-phase material composed of coarse aggregate, mortar matrix and the interfacial transition zone (ITZ) with nonlinear behaviour models are assumed for the mesoscopic level. The coarse aggregates are randomly generated from a certain grading curve and placed in the mesoscale subdomain, using the "take-and-place" method. The mesh fragmentation technique is employed, as proposed by Manzoli et al. This technique is based on the use of interface finite elements with high aspect ratio, which along with the employment of a constitutive tensile damage model is able to represent the crack initiation, propagation and coalescence, considering the individual behaviour of each phase as well as their mutual interactions in the mesoscale HSC. The macroscopic and mesoscopic meshes are attached via coupling finite elements, which provide a rigid coupling between them. Three-point bending tests are simulated on beams with different aggregate size distribution. The numerical results are compared with those obtained by the experimental test results developed by Siregar et al.
At the mesoscopic level, the fracture behaviour of high strength concrete (HSC) can differ signif... more At the mesoscopic level, the fracture behaviour of high strength concrete (HSC) can differ significantly from the conventional strength concrete since the coarse aggregate may be the weakest phase of the composite. In this way, the influence of coarse aggregate type, size, and distribution can affect all the macroscopic mechanical responses, such as the ultimate tensile strength and fracture energy. The present work proposes a concurrent two-scale (macro and mesoscale) approach for HSC, in which (i) a linear elastic model with homogenized elastic properties is used for the macroscale and (ii) a three-phase material composed of coarse aggregate, mortar matrix and the interfacial transition zone (ITZ) with nonlinear behaviour models are assumed for the mesoscopic level. The coarse aggregates are randomly generated from a certain grading curve and placed in the mesoscale subdomain, using the "take-and-place" method. The mesh fragmentation technique is employed, as proposed by Manzoli et al. This technique is based on the use of interface finite elements with high aspect ratio, which along with the employment of a constitutive tensile damage model is able to represent the crack initiation, propagation and coalescence, considering the individual behaviour of each phase as well as their mutual interactions in the mesoscale HSC. The macroscopic and mesoscopic meshes are attached via coupling finite elements, which provide a rigid coupling between them. Three-point bending tests are simulated on beams with different aggregate size distribution. The numerical results are compared with those obtained by the experimental test results developed by Siregar et al.