Analysis of effective diffusivity of cement based materials by multi-scale modelling

作者：Dridi Wissem^*

来源：Materials and Structures, 2013, 46(1-2): 313-326.

DOI：10.1617/s11527-012-9903-5

• Microstructure
• Diffusion
• Homogenisation
• Cement
• Model

This paper presents a simplified composite model, which considers the contribution of each phase participating to the transport within OPC pastes and concretes. At the micrometer scale, the phases considered hereafter are capillary porosity (macro-porosity) and the Low Density and the High Density C-S-H both containing gel pores (nano-porosity). Predicted values of tritiated water (HTO) diffusivity in OPC pastes with various (w/c) ratios are confronted to experimental results with a good agreement. The approach is then extended to mortars and concretes scale where microstructure is described by a three-phase composite sphere assemblage. Here, elementary phase distribution is assumed to change as a function of distance from aggregate surface. Model results about HTO diffusivities of mortars and concretes are presented with some experimental values. The competition between the more diffusing ITZ zone and the less diffusing bulk matrix is investigated from a sensitive analysis. The dominance of the ITZ control is confirmed.

• 出版日期2013-1
• 单位中国地震局