耦合离子与水化产物间相互作用的水泥基材料氯离子传输模型
Chloride transport model for cement-based materials considering ion-cement hydrate interactions

钢筋混凝土结构为土木工程领域应用最广泛的结构形式，而氯离子诱发的钢筋锈蚀为降低混凝土结构耐久性的主要原因之一。在以往的研究中，基于Nernst-Planck方程的数值模型通常被用来模拟混凝土中离子的传输，进一步预测混凝土结构的服役寿命，然而这些数值模型并未考虑传输过程中离子与水化产物之间的热力学作用。因此，本文基于离子传输的物理化学作用的本质过程，建立了饱水状态下水泥基材料中多离子传输的数值模型。首先，采用表面络合模型和相平衡模型，建立了孔溶液中离子与水化产物间的热力学数值模型；然后，借助于算子分裂算法，求解了耦合热力学作用的Nernst-Planck方程多离子传输的有限元模型，得到了水化产物中各相成分、孔隙率及孔溶液中各自由离子浓度的演化规律。最后，通过已有文献的试验研究验证了本文建立的数值模型的准确性。 Reinforced concrete structures are widely used in civil engineering, but chloride-induced corrosion is one of the major factors that seriously deteriorate the durability of reinforced concrete structures. Thus, many numerical models have been developed to study the ion transport of cement-based material in the previous papers. However, most of these models could not consider the interactions between ions in the pore solution and cement hydrate. Based on the transport essential process of chloride in cement-based materials, this research presents a multi-species ionic transport model for cement-based materials coupling ion-cement hydrate interactions. Firstly, both the surface complexation model and the phase-equilibrium model were used to simulate the ion-cement hydrate thermodynamic interactions. Moreover, operator splitting algorithm was employed to solve the finite element numerical model of Nernst-Planck equation that coupling the ion-cement hydrate interactions, and then the variations of the content of each phase in cement hydrate, the porosity and the concentration of free ion in pore solution were discussed. Finally, the multi-species ionic transport numerical model was preliminarily verified by the experimental data published in the previous paper. 国家自然科学基金（51578190；51378156）；哈尔滨工业大学“青年拔尖人才计划”