Meso-scale modeling of concrete fracture by considering the aggregates and voids effect

Abstract

The mechanical behavior of concrete, similar to any other mixture, is affected by the properties and characteristics of its components. Therefore, to study more closely the behavior of concrete and to understand how its behavior is impacted by its constituent microstructure, it is necessary to properly consider the heterogeneity of its intrinsic structure. To consider the internal components of concrete, its different phases such as cement mortars, aggregates, interfacial transition zones and air voids can be modeled on meso scale. In this study, using meso modeling of concrete via finite element method, the modeling is examined and validated and the effect of different percentages of air voids and aggregates on some properties of concrete is investigated. The numerical modeling was performed by Mesh Fragmentation Technique and the distribution of aggregates and air voids by randomly. To consider the effect of the percentage of aggregates, the samples with 2% constant air void were selected. In addition, 20% to 50% percentage of aggregates with an increment of 10% was taken into account. Further, to investigate the effect of air void percentage in all samples, percentage of aggregate was considered 40%, and the amount of air void was considered 4% from 0 to 6% with an increment of 2%. The results show the high accuracy of modeling on meso scale as well as there is a negative correlation between the tensile strength of concrete and the percentage of air in concrete and the percentage of aggregate. Accordingly, airless sample and sample with 20% aggregate have the highest tensile strength with a value of 3.8 MPa.