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Vol.11, No1, 2011, pp.43-50 |
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MULTI SCALE MODELLING BASED ON THE HYGRO-COSSERAT THEORY FOR SELF DESICCATION DEFORMATION OF CEMENT MORTARS AT EARLY AGE J. Jeong1, P. Mounanga2, H. Ramézani3, M. Bouasker3 1) ESTP/IRC/LM-Lean Modeling-École Spéciale des Travaux Publics, du Bâtiment et de l'industrie (ESTP), Cachan cedex, France 2) GeM, UMR CNRS 6183 - Research Institute on Civil Engineering and Mechanics, University of Nantes, Saint-Nazaire, France 3) CRMD, UMR CNRS 6619- Research Center on Divided Materials, École Polytechnique de l'Université d'Orléans, France |
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Abstract In the present paper, we concentrate on the heterogeneous cement mortars and we treat them as Cosserat-based media. The autogenous shrinkage phenomenon at early age (from 1 to 3 days after mixing) is analysed by means of the Cosserat theory. The characteristic length scale parameter Lc in this theory helps us to change the size specimen from macro-scale to micro-scale using the theoretical size effect aspects. This methodology is also capable of treating crack initiation and their appearance in the cementitious matrix, surrounding the sand-inclusions, which should occur inside the Representative Volume Elementary (RVE) of mortar subjected to self-desiccation shrinkage during hydration at early age. By taking advantage of the Nonlinear Finite Element Analysis (NFEA), numerical experiments are performed. Numerical outcomes agree well with experimental observations from Scanning Electronic Microscopy (SEM) images. It concludes that the inclusions create not only a hygro stress concentration around the grains but also the number of inclusions should influence the network in the cementitious matrix. Keywords: cement based mortar, autogenous shrinkage, self desiccation, multi scale approach, hygro-Cosserat theory |
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full article (1.26 MB)
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