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为了快速获得水泥基材料钙溶蚀进程的有效实验数据,该文根据Fick定律和Gerard固液平衡方程,建立了软水环境下水泥砂浆圆柱体试件的钙溶蚀模型。给出了钙溶蚀过程中试件孔隙率和Ca(OH)2浓度分布的计算方法。进行了6M NH4Cl溶液中水泥砂浆圆柱体试件的加速钙溶蚀实验。利用称重法获得了钙溶蚀引起的试件孔隙率随溶蚀时间的变化规律。将圆柱体试件孔隙率的模型计算值与实验测试值进行了对比。进行了钙溶蚀过程中圆柱体试件孔隙率和Ca(OH)2浓度时空变化规律的数值分析。结果表明:孔隙率的模型计算结果与实测结果基本一致;在试件已溶蚀的深度内,孔隙率随溶蚀时间的增加而增加,试件表层的孔隙率在溶蚀初期增加较快,Ca(OH)2浓度随溶蚀时间的增加而降低且溶蚀初期的下降速率较大。
In order to quickly obtain effective experimental data of calcium dissolution process of cement-based materials, a calcium dissolution model of cement mortar cylindrical specimens in soft water environment was established according to Fick’s law and Gerard’s equation. The calculation method of porosity and concentration distribution of Ca (OH) 2 in the process of calcium dissolution is given. Accelerated calcium dissolution test of cement mortar cylinder specimens in 6M NH4Cl solution was carried out. The change law of the porosity of the specimen caused by calcium corrosion with the dissolution time was obtained by the weighing method. The calculated values of the porosity of the cylindrical specimen are compared with the experimental values. The numerical analysis of spatiotemporal variation of the porosity and Ca (OH) 2 concentration of cylinder specimens during the calcium dissolution process was carried out. The results show that the model calculation results of the porosity are basically consistent with the measured results. The porosity increases with the increase of dissolution time and the porosity of the surface layer increases rapidly during the initial dissolution, ) 2 concentration decreases with the increase of erosion time, and the rate of decline of the initial dissolution is higher.