Abstract
Concrete is considered as a heterogeneous material whose structure depends on the scale of observation. In our study, lightweight concrete is presented as a two-phase material at meso-scale level where coarse aggregates are embedded in the matrix. The interface between the two phases is considered perfect. The mechanical properties of lightweight aggregate concrete depend on the properties of the aggregates as well as on their volume fraction. Lightweight aggregates are more deformable than the mortar paste, which is not the case for normal concrete. Therefore, the study of the concrete behavior is more complex than for normal concrete. The presented work shows a numerical approach to study the elastic behavior of lightweight concrete taking into account its mesoscopic structure. This model allows to identify the homogeneous modulus of Young for different concrete samples. In order to validate the numerical results a comparison is made with experimental data. The numerical model is also used to identify the distribution of local principal stresses and principle strains in lightweight concrete. The identified values are used to study the failure mechanism in lightweight concrete while remaining in the elastic range. The numerical results show that the rupture mechanism in lightweight concrete is due to the failure of the mortar.