Compressive behavior of an idealized EPS lightweight concrete: size effects and failure mode

The purpose of this paper is to study size effects and failure mechanism of an idealized lightweight expanded polystyrene (EPS) concrete under compression. Two types of idealized 2D-EPS concrete specimens were obtained by perforating prismatic mortar sheets according to two periodic holes patterns with two diameter sizes. Then, specimens were subjected to standard uniaxial compressive tests. Results show that similar compressive strengths for the two specimens are obtained. Moreover, a specimens tensile failure mode with no cracks localization has been observed, which allows us to conclude that there is no size effect engendered by the quasibrittle behavior of the considered idealized EPS lightweight concrete. To simulate and predict numerically the absence of size effect on the compressive strength, periodic non-linear homogenization finite element calculations, with non-local Mazars damage model, were first carried out on unit cells of increasing size to determine the number of unit cells to form the representative volume element (RVE) of the considered idealized EPS lightweight concrete structures. Finally, uniaxial compressive tests on the two specimens have been simulated and non-local Mazars model parameters have been fitted to reproduce in a satisfactory manner similar compressive strengths for the two specimens, matching those obtained experimentally.