复合酸性气氛下基于微细观结构参数的混凝土中性化模型

Considering the atmosphere conditions with high concentrations of acidic gases, the anti-neutralization of concrete under multi-condition will be studied by analyzing the time-variant micro-meso structures and pore solution alkalinity of concrete. The key parameters to characterize the micro-meso structures relating to gas transport will be determined and the equivalent relationship between the level of tensile stress and the porous-structure related parameters can be established. Also the coefficient to characterize the influence of the dissolution rate and neutral reaction speed of acidic gases on the gas diffusion will be proposed. According to the theory of anomalous diffusion, Henry's and mass balance law, model analysis, laboratory validation, field-testing and computer simulation, the model will be provided to estimate the anti-neutralization performance of concrete by coupling the anomalous diffusion mechanism of composite acid gases and the micro-meso structure evolution, and the corresponding nonlinear numerical calculation system can be given. The proposed model will be verified with the neutral testing on the condition of tensile stress coupled with certain temperature and humidity. The parameters associated with the initial micro-meso structures will be recommended and the designing methods to enhance the anti-neutralization capability of concrete can be proposed using the numerical testing with the model and neutrolization testing of actural concrete structures. Thus this model can be used to predict and evaluate the anti-neutral performance of concrete experiencing the corrosion of composite acid gases under industrial air condition or inside tunnels accurately. In addition, this model can provide a theoretical support for the design of high anti-neutralization of concrete structures in fields with high concentration of acidic gases as compared to normal air atmosphere.

结合高浓度复合酸性气氛环境，把混凝土微结构和孔溶液碱度的时变分析手段，运用到多因素条件下混凝土中性化性能的研究中，确立影响酸性气体传输的关键微细观结构参数，建立拉应力水平与混凝土孔结构参数的等效关系，提出酸性气体溶解速度和中性化反应速度对气体扩散过程的影响系数；运用反常扩散理论、亨利定律及质量平衡理论，通过模型分析、实验验证、工程测试及计算机模拟，建立复合酸性气体反常扩散机制与混凝土微观结构特征相结合的混凝土中性化模型和非线性数值计算系统；并采用拉应力与环境温湿度条件共同作用下的混凝土中性化试验进行验证；通过数值试验和对实际结构混凝土的中性化测量，提出增强混凝土抗中性化性能的初始微细观结构参数与设计方法；利用该模型可以准确地预测和评估工业大气环境或交通隧道内复合酸性气体作用下混凝土的抗中性化性能，为酸性气体浓度较高区域混凝土结构的抗中性化性能设计提供理论依据。

以水灰比为0.3～0.45水泥混凝土为工业大气及类工业大气环境中代表性结构混凝土，研究孔隙率、孔径分布、连通性及氢氧化钙含量随着养护条件等环境因素的时变规律；并根据胶凝材料水化动力学理论，提出复合胶凝材料的水化动力学方程，建立混凝土基体氢氧化钙含量和毛细孔隙率的动态演化模型。采用CT扫描技术原位分析了混凝土细观孔结构参数在碳化侵蚀前后的变化规律；提出了用于计算复合酸性气体浓度较高的公路交通衬砌混凝土湿含量时变规律的湿度模型。建立了适用于工业大气或类工业大气环境中混凝土，并考虑荷载水平和复合酸性大气共同作用影响的二氧化碳气体传输模型，可以准确地预测和评估工业大气环境或交通隧道内复合酸性气体作用下混凝土的抗中性化性能，为酸性气体浓度较高区域混凝土结构的抗中性化性能设计提供理论依据。综合上述结果，本课题研究为研究工业大气及类工业大气环境气氛下的结构混凝土抗中性性能提升技术奠定了坚实的工作基础。项目资助已发表SCI收录论文3篇，EI收录论文1篇，还有一篇EI期刊录用待发表。协助培养了硕士生3名均已取得硕士学位，独立培养硕士生2名。项目投入经费25万元，支出19.1100万元，各项支出基本与预算相符，剩余经费5.8900万元，剩余经费计划用于本项目研究后续支出。