Influence of the macro-porosity and the meso-structure on the dynamic properties of concrete
Résumé
Traditionally, the variability of concrete properties (in statics) is represented - in classical ma- croscopic models - using stochastic tools that can be complex and have to be identify with a large number of experimental tests. However, this phenomenon is usually linked to a "deterministic" characteristic of the ma- terial : the multiple defaults that can be found in the cement paste matrix. This works intends to explore the influence of the heterogeneous meso-structure coupled with an explicit representation of the macro-porosity on the dynamic properties of concrete like material. For this purpose we use FE simulations with a cohesive ap- proach and an explicit representation of the meso-structure, including macro-pores in the cement paste. In this kind of material, heterogeneities (in our case the biggest aggregates) have sizes of the order of tens of millime- ters with defaults (pores) in the matrix we can imagine that they will influence fracture properties. To obtain a realistic description of the meso-structure we used a distribution of the aggregate according to the Fuller distri- bution (Fuller & Thompson 1907) and the distribution of the macro-porosity is computed by analyzing images of real concrete specimens obtained by X-ray microtomography.
Domaines
Génie civil
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