A new discrete element constitutive behaviour of concrete in the YADE platform H. BENNIOU 1,2 , Y. MALECOT 1,2 , M. BRIFFAUT 1 and L. DAUDEVILLE 1,2 1 Univ. Grenoble Alpes, 3SR – UMR 5521, BP53 38041 Grenoble Cedex 9, France 2 CNRS, 3SR – UMR 5521, BP53, 38041 Grenoble Cedex 9, France E-mail: hicham.benniou@3sr-grenoble.fr, yann.malecot@3sr-grenoble.fr, matthieu.briffaut@3sr- grenoble.fr, Laurent.daudeville@3sr-grenoble.fr ABSTRACT Deformation and deterioration mechanisms of concrete are strongly influenced, on one hand, by the mesoscopic scale heterogeneity (large aggregates and macropores) and, on the other hand, by the possible presence of free water at the microscopic level of cement hydrates. This observation remains valid both at very low strain rate (concrete creep) and under severe dynamic loading (impact on a concrete structure) and both in tension and compression stress states. The proposed new Discrete Element Model (DEM) addresses the macroscopic behaviour of concrete taking into account the presence of free water in pores. Thanks to interactions between spherical discrete elements (DE) of different radii and masses, DEM allows an easy modelling of cracking in order to represent the macroscopic behaviour of concrete. In this new constitutive model, cracking and compaction are modelled at the interaction level between DE, free water effects are taken into account by introducing a dependence between the possible water saturation and the plasticity, this dependence is carried out thanks to a modified Mohr-Coulomb criterion. The present numerical model has been implemented within the YADE (Yet Another Dynamic Engine) code. Once the assembly has been set, pairs of initially interacting discrete elements are identified. Using the non-linear constitutive equations for each interaction, the explicit time integration of motion equations gives new displacement and velocity for each discrete element. The macroscopic behaviour of concrete can be reproduced thanks to this discrete element model. Triaxial compression tests performed with the GIGA press under triaxial, oeodometric and hydrostatic stress paths on ordinary concrete samples were simulated with the proposed DE model. The comparison of experimental and simulation results are shown. REFERENCES [1] Poinard C., Piotrowska E., Malecot Y., Daudeville L., Landis E. 2012. Compression triaxial behavior of concrete: the role of the mesostructure by analysis of X-ray tomographic images. European Journal of Environmental and Civil Engineering. 16(supp 1): 115-136. [2] Vu X.H., Malécot Y., Daudeville L., Buzaud E. (2009) Experimental analysis of concrete behavior under high confinement: Effect of the saturation ratio, International Journal of Solids and Structures, 46(5):1105- 1120 [3] Gabet T., Malécot Y., Daudeville L. (2008) Triaxial behaviour of concrete under high stresses: Influence of the loading path on compaction and limit states, Cement and Concrete Research, 38(3):403-412 [4] Poinard C. Malecot Y. Daudeville L. (2010). Damage of concrete in a very high stress state: Experimental investigation. Materials and Structures. 43(1-2): 15-29. [5] Gabet T., Vu X.H., Malecot Y., Daudeville L. (2006). A new experimental technique for the analysis of concrete under high triaxial loading. J. Phys IV. 134: 635-640. [6] Rousseau J., Frangin E., Marin P., Daudeville L. (2008). Damage prediction in the vicinity of an impact on a concrete structure: a combined FEM/DEM approach. Computers and Concrete. 5(4): 343-358. [7] Kozicki, J., Donzé, F. V. (2009). Yade-open dem: an open-source software using a discrete element method to simulate granular material. Engineering Computations, 26(7), 786-805.