中文摘要：

考虑矿物掺合料种类和掺量的影响,结合混凝土中CO2的扩散规律以及可碳化物质的质量守恒定律,以CO2扩散系数、碳化反应速率系数和混凝土中可碳化物质的量为控制参数,研究建立了矿物掺合料混凝土碳化分析的非线性多场耦合模型,并利用试验数据进行了对比验证。首先基于水泥水化、矿物掺合料二次水化以及混凝土碳化的机理,结合Fick第二定律和化学反应平衡方程,建立了矿物掺合料混凝土碳化分析的非线性多场耦合模型;然后考虑温度、相对湿度、水胶比以及矿物掺合料种类和掺量等因素的影响,提出了模型中CO2扩散系数、碳化反应速率系数、可碳化物质的量等控制参数的计算公式;最后利用加速碳化试验数据对比验证了该模型的有效性,并结合混凝土中CO2、可碳化物质和p H值的分布规律,揭示了温度、相对湿度、水胶比、矿物掺合料种类和掺量等因素对混凝土碳化深度的影响规律。

英文摘要：

Considering the influences of the type and quantity of the mineral admixtures,a nonlinear multi-field coupled model for carbonation analysis of concrete with mineral admixtures was established and verified by combining the rule of diffusion of CO2 within concrete with the law of conservation of mass for carbonatable substances.The diffusion coefficient of CO2,the coefficient of reaction rate between CO2 and carbonatable substances,and the kind and dosage of the carbonatable substances were adopted as the governing parameters in the proposed model.According to the Fick＇s second law of diffusion and the balance chemical equations,a nonlinear multi-field coupled model for carbonation analysis of concrete with mineral admixtures was established based on the mechanism of cement hydration,second hydration of minerals and concrete carbonation first.Then,computation expressions of model parameters,such as the diffusion coefficient of CO2 within concrete,the coefficient of reaction rate between CO2 and carbonatable substances,and the amount of the carbonatable substances,were developed by taking into account the influences of the temperature,relative humidity,water to binder ratio,and mineral admixtures on carbonation.The proposed model was verified by comparing with experimental data and the influences of the temperature,relative humidity,water to binder ratio and mineral admixtures on carbonation depth were quantificationally investigated based on the distribution of CO2,carbonatable substances and the pH value within the concrete.