氯盐在损伤和开裂混凝土中的传输机理及多尺度本构模型

项目名称： 氯盐在损伤和开裂混凝土中的传输机理及多尺度本构模型

项目编号： No.51478278

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 建筑环境与结构工程学科

项目作者： 孙国文

作者单位： 石家庄铁道大学

项目金额： 83万元

中文摘要： 要揭示混凝土在服役环境中的劣化本质，其核心问题是研究氯盐等侵蚀性介质在损伤及开裂混凝土中的传输行为。混凝土的多孔、多相和多尺度特征，决定了其传输行为的研究及传输本构的建立需采用多尺度过渡法。项目首先对影响氯盐传输的微结构通道特征参数进行定量表征：通过凝胶材料水化机理研究，建立水化产物体积分数与其细度、养护龄期、水胶比和环境温湿度之间定量关系，建立非球形骨料粒子表面的界面过渡区(ITZ)体积分数和其ITZ的孔结构特征预测模型，建立裂缝曲折度、裂缝含量以及裂缝宽度之间的定量关系；其次基于细观力学理论和多孔介质理论，建立含椭球形多类夹杂的Mori-Tanaka法和相互作用直推法传输模型；第三通过多尺度过渡法分别建立混凝土在不同饱水度和荷载作用下，其微结构与氯离子传输本构模型并进行数值计算；最后通过一系列微细观测试手段和宏观试验方法对所建本构模型进行验证，为混凝土耐久性设计和寿命预测奠定基础。

中文关键词： 混凝土；多尺度；传输；氯离子；微结构

英文摘要： To reveal the deterioration essence of modern concrete in service environment, it is necessary to establish the constitutive relation between the micro-structure of concrete and its macro-transport performance. The features of modern concrete, as porous, multi-phase and multi-scale features, require the use of multi-scale scheme to establish transport constitutive between micro-structure of concrete and its macrostructure. In this project, First, characteristics of the micro-structural parameters of chloride transport channel is quantitatively determined. Based on hydration mechanism of gel material and a prediction model is establish between the volume fraction of gel material and its fineness, curing age, water to binder ratio, environmental temperature and humidity; the prediction models of the volume fraction and pore structure characteristics in interfacial transition zone between aggregate and bulk cement are established; the quantitative relationship between the tortuosity connectivity and content of crack is proposed; quantitative characterization of the above-mentioned microstructure characteristic parameters is the basis input parameters of the multi-scale transport theory. Based on micromechanics and the porous media theory, the transport model of Mori-Tanaka andinteraction direct derivation scheme containg multiple class ellipsoid inclusions is established and the transport constitutive model is essentially built between modern concrete microstructure and chloride ion transport through the optimized multi-scale transition scheme under the condition of saturation degree and loads and then conduct numerical calculation . Finally, a series of micro- and macro-test methods are employed to validate the constitutive model. The above-mentioned results can provide the foundation for the durability design and life prediction of concrete.

英文关键词： concrete;multi-scale;transport;chloride ion;microstructure