湿热耦合机制下混凝土早龄期收缩变形多尺度预测模型研究

项目名称： 湿热耦合机制下混凝土早龄期收缩变形多尺度预测模型研究

项目编号： No.51309090

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 水利工程

项目作者： 赵海涛

作者单位： 河海大学

项目金额： 25万元

中文摘要： 混凝土早龄期裂缝严重影响建筑物正常使用和耐久性。混凝土早龄期收缩变形是早期开裂重要原因，但有关混凝土早龄期收缩变形定量描述和变化规律研究至今还不成熟。混凝土早期收缩变形与其内部湿度、微观孔结构密切相关，而温度、湿度耦合作用对其内部湿度、微观孔结构有重要影响。课题拟通过试验研究并结合国内外研究成果，建立水泥浆体微观孔结构模型；通过理论分析和数值模拟，基于多孔介质传热传质理论，建立混凝土早龄期非等温饱和-非饱和湿热耦合传输分析方法，编制有限元程序研究混凝土内部湿度发展变化规律；采用等效应力原理和多尺度理论，建立混凝土早龄期收缩变形多尺度预测模型，提出典型类型构件典型影响因素下收缩变形取用方法。课题提出建立的混凝土早龄期收缩预测模型具有空间变形梯度特征，更符合混凝土结构实际变形；联系了混凝土内部状态变量和宏观性能，可望具有更高预测精度。研究成果可为混凝土早龄期开裂风险评价、裂缝控制提供基础条件。

中文关键词： 混凝土；湿热耦合；收缩变形；多尺度；预测模型

英文摘要： The serviceability and durability of buildings are strongly influenced by the cracks of concrete at early ages. The shrinkage deformation is generally considered as one of most important factors which results in cracks of early-age concrete. So far, the variation law of shrinkage deformation hasn't been solved absolutely. The shrinkage deformation of early-age concrete is closely related to the internal relative humidity and microscopic pore structure, which are greatly influenced by the coupling effect of temperature and humidity. This study aims to achieve these goals as follows. First, a microscopic pore structure model of cement paste is built based on experiment and existing research results. Sencond, a coupled hygro-thermal transportation model of early-age concrete under nonisothermal and saturated-unsaturated condition is established based on heat-mass transfer theory of porous media. Meanwhile, a finite element program for studying the internal relative humidity of concrete is developed. At last, a multiscale prediction model of shrinkage deformation for early-age concrete is given using the effective stress principle and multiscale theory, and a method is proposed to determine the shrinkage deformation in typical component and with typical influence factors. The spatial deformation gradient characteri

英文关键词： Concrete；Hydro-thermal；Shrinkage deformation；Multiscale；Predition model