A Probabilistic Model for the Evolution of Porous Structure Caused by Solid-Phase Precipitation/Dissolution within Building Materials

Abstract

Saline intrusion is a critical issue in building material because of the severe damages caused by the salt precipitation/dissolution process, especially for the porous material, which has good connectivity. When porous material is exposed to aggressive ambient, the pore structure, not only porosity but also pore size distribution, will be altered by salt precipitation/dissolution. As one of the most significant characteristics in the porous material, pore size distribution is always paid much attention in many literatures. However, a quantitative and practical determination method is still absent. This work aims to establish a probabilistic model to investigate the pore size distribution induced by solid-phase precipitation/dissolution. First, a lognormal distribution is proposed for the simulation of initial pore size distribution tested by the MIP method. Then we develop a probabilistic-based porous network to represent the evolution of microstructure due to precipitation/dissolution. To this end, two different transformation models are constructed to interpret the relation between initial pore radius and modified pore radius before and after precipitation/dissolution. With this probabilistic-based porous network, we could illustrate the precipitated profiles that evolve near the capillary interface during the salt precipitation/dissolution process for a given porosity and water saturation degree. Such a method could be used to interpret the mechanism of the local precipitation/dissolution process in pore scales, which cannot be implemented by experimental measurements.

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