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为了预测水泥基复合材料的离子扩散性能并进而将其用于耐久性研究与寿命预测模型中,基于Einstein-Smoluchowski公式,提出了一个将宏观离子扩散行为和微观粒子Brown运动相关联的方法。为了验证这个方法的可靠性,首先用计算机模拟的方法生成一个水化水泥浆体的微观结构(HYMOSTRUC3D),然后用自回避随机行走算法预测这个微观结构的离子有效扩散系数。在这个过程中,应用统计分析的方法确定了水泥浆体微观结构的代表性体积单元的大小,此后在这个代表性体积单元的基础上,通过与文献数据比较,验证了用该方法预测水泥浆体宏观氯离子扩散行为的合理性,最后应用该方法预测了水泥浆体氯离子有效扩散系数随水胶比和养护龄期变化的关系。
In order to predict the ion diffusion properties of cement-based composites and then to use them in the durability research and life prediction model, a method based on Einstein-Smoluchowski formula is proposed to correlate macroscopic ionic diffusion behavior with microscopic particle Brownian motion. In order to verify the reliability of this method, a hydrated cement paste microstructure (HYMOSTRUC3D) was first generated by computer simulation and then the ion diffusion coefficient of this microstructure was predicted by a self-avoiding random walking algorithm. In this process, the size of the representative volume element of cement paste microstructure was determined by statistical analysis. Based on this representative volume element, the comparison with the literature data verified that the method of predicting the volume fraction of cement paste The macromolecular chloride ion diffusion behavior is reasonable. Finally, this method is used to predict the relationship between the effective diffusion coefficient of chloride ion and the change of water-cement ratio and curing age.