Concreteisathreephasematerialcomprisingofaggregates,matrixandinterfacetransition zone (ITZ) between the aggregate and matrix. In general, the microstructure of ITZ is different than that of bulk mortar and is considered to be the weakest link in concrete. It is important to understand the properties of ITZ…
Concreteisathreephasematerialcomprisingofaggregates,matrixandinterfacetransition zone (ITZ) between the aggregate and matrix. In general, the microstructure of ITZ is different than that of bulk mortar and is considered to be the weakest link in concrete. It is important to understand the properties of ITZ and its effect on physical, mechanical and fracture properties of concrete. In this work, an attempt has been made to develop an analytical model to investigate the fracture properties in concrete namely, critical fracture energy while taking into account the effect of interfacial transition zone at mesoscopic level. The mathematical model has been developed from the fundamentals using the principle of dimensional analysis and theory of intermediate asymptotic. Various important parameters, which influence the fracture energy, are volume fraction and elastic modulus of constituents, maximum aggregate size, water to cement ratio and thickness and porosity of ITZ and have been considered in this study. The thickness and porosity of the transition zone has been analyzed as a function of degree of hydration and is seen to have significant effect on fracture energy. Resultshaveshownthatthefractureenergyofconcreteincreasewiththeincreaseinaggregate size whereas decreases with the increase in transition zone porosity. The effect of water to cement ratio on fracture energy of concrete has also been studied and presented in the paper.