超低温及其冻融循环下混凝土水热耦合传输机制与温度变形行为

项目名称： 超低温及其冻融循环下混凝土水热耦合传输机制与温度变形行为

项目编号： No.51478348

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： 蒋正武

作者单位： 同济大学

项目金额： 88万元

中文摘要： 超低温是混凝土材料应用最极端环境条件之一，其对混凝土各项性能影响十分显著，探索超低温下混凝土温度变形行为及其相关关键科学问题对进一步认识超低温特种环境下混凝土特性和指导工程应用具有重要的科学意义。本项目首先设计0～-190℃自动控温超低温养护箱、超低温混凝土变形性能测试方法与装置；研究不同尺度下混凝土内部温度梯度及温度场分布；运用多孔介质水热传输理论，建立超低温下混凝土水热耦合传输模型，并模拟分析水热传输过程及其耦合效应，探明超低温下混凝土水热耦合传输机制；采用冷冻扫描电镜、热孔计法等手段，揭示超低温及其冻融循环作用下混凝土孔结构及微观结构演变规律；研究超低温及其冻融循环下混凝土温度变形行为规律及影响因素；探明超低温及冻融循环下混凝土水热传输过程与温度变形关系，从而阐明超低温及其冻融循环下混凝土水热耦合变形机理。研究成果可为解决混凝土在超低温极端环境下应用的科学问题与关键技术提供科学指导。

中文关键词： 超低温；冻融；温度变形；水热耦合；传输机制

英文摘要： Cryogenic temperature is one of the extreme application conditions of concrete, which has great influence on each properties of concrete. Therefore, it is of great scientific significance of exploring the thermal deformation of cryogenic concrete and its related scientific problems on practical applications of concrete in cryogenic conditions. Firstly, a cryogenic curing box with an automatic temperature (0～-190℃) control system is designed. A novel method to test thermal strain of concrete at cryogenic temperatures is proposed and the corresponding testing device is designed. Secondly, the temperature gradient and temperature field of concrete in different sizes are investigated. Based on the water and heat transter theory of porous materials, a coupled water-heat transfer model for cryogenic concrete is established. This model will be used to simulate the process of water-heat transfer and to help explain their coupling effects. Consequently, the coupled water-heat transfer mechanism of concrete at cryogenic temperatures is ascertained. Thirdly, the evolution of microstructure within concrete under the conditions of cryogenic temperature and its cryogenic freeze-thaw cycles is to be discovered using testing methods such as cryogenic SEM and thermoporometry. The thermal strains of concrete and its influential factors under cryogeinc temperature and its freeze-thaw cycles are to be investigated. The relationship between the water-heat transfer process mechanism and temperature deformation under the condition of cryogenic temperature and its freeze-thaw cycles is discussed. Therefore, the coupled water-heat deformation mechanisms at cryogenic temperatures and during cryogenic freeze-thaw cycles can be proposed. The research achievements above will provide scientific guidance for solving scientific problems and key techniques of practical applications of concrete under the extreme cryogenic conditions.

英文关键词： cryogenic temperature;freezing-thawing;temperature deformation;water-heat coupling;transfer mechanism