The multi-scale numerical simulation method, able to represent the complexity of the random structures and capture phase degradation, is an effective way to investigate the long-term behavior of concrete in service and bridges the gap between research on the material and on the structural level. However, the combined chemical-physical deterioration mechanisms of concrete remain a challenging task. The purpose of this paper is to investigate the degradation mechanism of concrete at the waterline in cold regions induced by combined calcium leaching and frost damage.
With the help of the NIST’s three-dimensional (3D) hydration model and the random aggregate model, realistic 3D representative volume elements (RVEs) of concrete at the micro-, the meso-, and the macro-scales can be reconstructed. The boundary problem method is introduced to compute the homogenized mechanical properties for both sound and damaged RVEs. According to the damage characteristics, the staggering method including a random dissolution model and a thermo-mechanical coupling model is developed to simulate the synergy deterioration effects of interacted calcium leaching and frost attacks. The coupled damage procedure for the frost damage process is based on the hydraulic pressure theory and the ice lens growth theory considering the relationship between the frozen temperature and the radius of the capillary pore. Finally, regarding calcium leaching as the leading role in actual engineering, the numerical methodology for combined leaching and frost damage on concrete property is proposed using a successive multi-scale method.
On the basis of available experimental data, this methodology is employed to explore the deterioration process. The results agree with the experimental ones to some extent, chemical leaching leads to the nucleation of some micro-cracks (i.e. damage), and consequently, to the decrease of the frost resistance.
It is demonstrated that the multi-scale numerical methodology can capture potential aging and deterioration evolution processes, and can give an insight into the macroscopic property degradation of concrete under long-term aggressive conditions.
This work was supported by the CRSRI Open Research Program (Program SN: CKWV2014216/KY), China National Natural Science Foundation (Grant Nos 51409167, 51139001), the Fundamental Research Funds for the Central Public Welfare Research Institutes of NHRI (Grant Nos Y714015, Y715018), the Ministry of Water Resources Public Welfare Industry Research Special Fund (Grant Nos 201401022, 201501036), and the Task Project in Scientific and Technological Research of Water Conservancy for Henan Province (Nos GG201532, GG201546).
Hu, J. (2016), "Multi-scale numerical simulation analysis for influence of combined leaching and frost deteriorations on mechanical properties of concrete", Multidiscipline Modeling in Materials and Structures, Vol. 12 No. 4, pp. 648-671. https://doi.org/10.1108/MMMS-03-2016-0013Download as .RIS
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