混凝土温度相关热传导行为细观分析  

Mesoscopic Analysis of the Temperature-dependent Thermal Conduction Behavior Within Concrete

作　　者：张仁波[1] 金浏[1] 杜修力[1] ZHANG Renbo;JIN Liu;DU Xiuli(Key Laboratory of Urban Security and Disaster Engineering,Ministry of Education,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124

出　　处：《北京工业大学学报》2018年第12期1503-1512,共10页Journal of Beijing University of Technology

基　　金：国家重点研发计划专项资助项目(2016YFC0701100);国家"973"计划资助项目(2015CB058000)

摘　　要：为了研究非均质混凝土的热传导行为,考虑混凝土内部结构的非均质性及材料热工参数的温度相关性,将混凝土视为骨料、砂浆和界面过渡区组成的三相复合材料,建立二维/三维随机骨料细观数值模型.在模型中,砂浆与骨料热工参数的温度相关性通过拟合现有文献试验数据获得,界面过渡区的参数则通过与试验结果对比反演得到.基于此,对混凝土热传导行为进行了细观有限元模拟.模拟结果与试验结果吻合良好,从而说明了该数值方法的合理性与准确性.模拟结果表明:考虑材料热工参数的温度相关性,可以更准确地预测混凝土的宏观有效导热系数(effective thermal conductivity,ETC)及温度场;骨料形状对有效导热系数的影响可忽略,而由于导热系数的差异,骨料类型的影响应该予以考虑;混凝土有效导热系数随骨料体积分数增大而增大,随温度升高而降低.Considering the heterogeneity of concrete and temperature-dependency of materials,both 2D and 3D random aggregate structures of concrete were established to analyze the heat conduction behavior of heterogeneous concretes.In the numerical homogenization technique,concrete was regarded as a heterogeneous material consisting of three components,i.e.,aggregate,mortar matrix and the interfacial transition zones(ITZs).The temperature-dependent thermal properties of mortar and aggregate were obtained based on the experimental data from the available literatures and those of the ITZ were determined by comparing the simulation results with measured values.The heat conduction equations were solved by using finite-element method.Good agreement between the present simulation results and available test observations illustrates the accuracy and reasonability of the developed approach.The simulation results indicate that not only the effective thermal conductivity(ETC)but also a more accurate temperature field of concrete can be obtained by the meso-scale simulation method considering temperature-dependency of materials’thermal properties.Aggregate shape has a negligible influence on the ETC of concrete while the effect of aggregate type cannot be ignored due to their different thermal conductivities.The ETC of concrete increases with increasing aggregate content while decreases when the temperature increases.

关 键 词：混凝土 热传导 非均质性 温度相关性 有效导热系数 温度场 

分 类 号：TU528[建筑科学—建筑技术科学]