孔隙率和损伤演化加速混凝土碳化的模拟  

Simulation of accelerated carbonation in concrete due to porosity and damage evolution

作　　者：林其武 章青[1] 顾鑫[1] 陈宣东 Lin Qiwu;Zhang Qing;Gu Xin;Chen Xuandong(Hohai University,Nanjing 210098,China)

机构地区：[1]河海大学,江苏南京210098

出　　处：《能源与环保》2024年第5期164-170,180,共8页CHINA ENERGY AND ENVIRONMENTAL PROTECTION

基　　金：国家自然科学基金高铁联合基金(U1934206)。

摘　　要：外荷载引起的混凝土损伤加速了混凝土的碳化进程,引入孔隙率和损伤变量修正了介质传输方程的扩散系数,发展了Papadakis的经典碳化模型,构建了特定外界环境下以孔隙率和损伤度为自变量的混凝土碳化模型。建立了可反映混凝土细观结构特征的随机骨料模型,基于有限元法模拟了CO_(2)在混凝土中的传输—反应过程,探究了外荷载和湿热环境共同作用下混凝土中介质浓度及孔隙率的变化规律、碳化发展和损伤演化过程。研究结果表明,外荷载的作用增加了混凝土的碳化深度及其非均匀性。研究成果揭示了荷载作用下混凝土的加速碳化机制,可为混凝土耐久性设计和寿命预测提供参考。Damage in concrete induced by external loading accelerates the carbonation process.This study introduced porosity and damage variables to modify the diffusion coefficient in the medium transport equation,developing Papadakis's classical carbonation model.A concrete carbonation model was constructed with porosity and damage degree as independent variables under specific external environments.A random aggregate model reflecting the microstructural characteristics of concrete was established,and the transport-reaction process of CO_(2)within concrete was simulated using the finite element method.The study explored the patterns of change in medium concentration and porosity,as well as the development of carbonation and damage evolution processes under the combined effects of external loading and a moist-thermal environment.Results indicate that the action of external loading increases both the depth and non-uniformity of concrete carbonation.These findings reveal the mechanism of accelerated carbonation in concrete under loading,providing references for durability design and life prediction of concrete.

关 键 词：混凝土碳化 孔隙率 应力损伤 数值模拟 细观结构 

分 类 号：TU528[建筑科学—建筑技术科学]