环境水侵蚀下水泥净浆钙溶蚀的模拟与验证

发布时间：2018-06-07 15:14

本文选题：钙溶蚀 + 水泥净浆　；参考：《水利水运工程学报》2017年03期

【摘要】：钙溶蚀是导致水环境中混凝土等水泥基材料耐久性退化的重要原因之一。为获得软水环境下水泥净浆的钙溶蚀过程,首先,基于Fick定律及质量守恒定律,利用钙溶蚀过程中材料骨架内固体钙含量和孔溶液中钙离子浓度之间的化学平衡关系及Newton边界条件,建立软水环境下水泥净浆的钙溶蚀模型,并通过有限差分法,对该模型进行数值求解;其次,进行不同水灰比的水泥净浆试件在6M NH4Cl溶液中的加速钙溶蚀试验,测定该溶液中各水泥净浆试件在不同溶蚀时间的钙硅比与孔隙率,并将所建立模型的计算结果与实测结果进行对比分析,验证模型的合理性;最后,利用验证后的钙溶蚀模型,数值分析了环境水侵蚀下水泥净浆薄板孔溶液中钙离子浓度、固体钙含量及孔隙率的时空分布规律。结果表明,模型的计算结果与试验测试结果基本一致;溶蚀前期,试件中固体钙含量下降速度和孔隙率增加速率均较大,溶蚀后期,试件固体钙溶蚀速率和孔隙率的增加速率逐渐减小。
[Abstract]:Calcium dissolution is one of the important reasons for the durability degradation of concrete and other cement-based materials in water environment. In order to obtain the calcium dissolution process of cement paste in soft water environment, first, based on the law of Fick and the law of mass conservation, the chemical equilibrium between the calcium content in the skeleton of the material and the calcium ion concentration in the pore solution is used in the process of calcium dissolution. The calcium dissolution model of cement paste in soft water environment was established by the relationship and Newton boundary condition, and the model was solved numerically by the finite difference method. Secondly, the accelerated calcium dissolution test of cement paste specimens with different water cement ratio in 6M NH4Cl solution was carried out, and the calcium silicon in different dissolution time of the cement paste specimens in the solution was determined. Compared with the porosity, the calculated results and the measured results are compared and analyzed to verify the rationality of the model. Finally, the calcium ion concentration, the solid calcium content and the porosity distribution in the pore solution of the cement paste plate are numerically analyzed with the validated calcium dissolution model. The results show that the model is a model. The calculated results are in agreement with the test results, and the decrease rate of solid calcium content and the increase rate of porosity are all higher in the pre dissolution test, and the increase rate of solid calcium dissolution rate and porosity decreases gradually in the later period of dissolution.
【作者单位】：南京理工大学理学院土木工程系;
【基金】：国家自然科学基金资助项目(51378262,51078186) 江苏省自然科学基金资助项目(BK20141396)
【分类号】：TQ172.1

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