人工模拟和自然氯盐环境下混凝土氯盐侵蚀相似性研究
发布时间：2018-11-07 20:46
【摘要】：摘要：氯离子引起钢筋锈蚀是导致氯盐环境中钢筋混凝土结构耐久性退化的主因；建立人工模拟和自然氯盐环境中混凝土氯盐侵蚀的相似关系,对准确地预测氯盐环境中混凝土结构的使用寿命和评估其耐久性具有重要意义。若要建立人工模拟和自然氯盐环境中混凝土氯盐侵蚀的相似关系,前提条件则是先确立适宜的人工模拟环境试验制度以保证两种环境中混凝土氯盐侵蚀过程和机理的相似；而确立人工模拟环境试验制度的核心工作则是解决模拟环境参数(如温度、湿度、润湿时间、循环时间和风速等)取值依据和范围问题。然而,现有研究在试验制度和依据方面尚未达成共识,研究成果难以定量对比。本文在总结已有研究的基础上,提出了基于混凝土内部微环境响应相似的人工模拟环境试验制度的设计方法；基于该试验制度和混凝土氯盐侵蚀相似准则模型,构筑了人工模拟和自然环境中混凝土氯盐侵蚀相似关系。研究内容如下： (1)基于混凝土内部微环境层次理念,建立了分段形式的自然环境温/湿度作用谱和混凝土内微环境温/湿度响应谱模型。摒除了将自然环境直接等效为混凝土内微环境观念的不足,分析了环境因素作用和混凝土内部微环境响应间的异同,探讨了湿度采用相对湿度与水汽密度表达形式间的关联和适用范围。研究结果表明：混凝土内微环境与自然环境间的异同主要表现为波动周期相等、相位滞后和峰值衰减等方面,不可将自然环境简单地视为混凝土内部微环境；采用水汽密度表达形式可更好地描述自然环境湿度变化规律和表征混凝土内部微环境湿度特征。 (2)通过探讨人工模拟环境中混凝土内部微环境温度响应,建立了混凝土内部微环境温度响应模型,并提出了求解模型数值解的新方法。分析表明：因环境作用机制的不同使得人工模拟环境中混凝土内微环境响应规律有别于自然环境,人工模拟环境中混凝土内微环境响应实测结果与理论模型曲线吻合较佳。 (3)建立了含温度和风速参数的混凝土水分传输表面因子模型,并采用数值模拟法探讨了风速对混凝土内湿度分布状态的影响。数值模拟结果表明：若风速和临界干燥时间超过定值(风速约为3.0m/s,临界干燥时间约为13h),则可将模拟环境湿度等效为混凝土与环境间的界面湿度；这是因混凝土内部、混凝土表层和外界环境间的水分传输量达到平衡态造成的。 (4)提出了基于混凝土内部微环境响应相似的人工模拟环境试验制度的设计方法。通过分析混凝土内部微环境响应规律和边界条件,确立了人工模拟环境试验参数(如温度、湿度、润湿时间、干燥时间、循环风速和氯盐溶液浓度等)取值依据和范围,解决了现有研究中人工模拟试验制度参数取值依据不充分的难题。基于混凝土表层内水分传输模型,分析了混凝土水灰比、混凝土初始饱和度和湿度梯度对干湿平衡时间比和水分影响深度的影响；还提出了采用BET等温吸附曲线求解混凝土内水分特征曲线的新途径。结果表明：混凝土干湿平衡时间比和水分影响深度是确立人工模拟试验制度的重要指标。 (5)推导了人工模拟和自然氯盐环境混凝土氯盐侵蚀相似准则模型和相似关系,并为实际工程测试数据所验证。通过建立混凝土氯离子扩散系数和表层氯离子对流区深度模型,利用人工模拟试验制度和研究方法评估了氯盐环境中典型混凝土结构的耐久性。结果表明：混凝土表层的氯离子浓度与高程和距海距离间的关系均符合S曲线,人工模拟和自然环境中混凝土氯盐侵蚀间的差异主要表现为混凝土表层氯离子含量、氯离子对流区深度和扩散系数等方面；特定的人工模拟环境试验和自然环境中混凝土氯盐侵蚀的相似率为定值。
[Abstract]:Abstract: The corrosion of the steel bar caused by the chloride ion is the main cause of the deterioration of the durability of the reinforced concrete structure in the chlorine salt environment, and the similar relation between the corrosion of the concrete and the chloride in the environment of artificial simulation and natural chlorine salt is established. It is of great significance to accurately predict the service life of the concrete structure in the chlorine salt environment and to evaluate its durability. In order to establish a similar relationship between the corrosion of the concrete and the chloride in the environment of artificial simulation and natural chlorine salt, it is necessary to establish a suitable artificial simulation environment test system to ensure that the corrosion process and mechanism of the concrete chlorosalt in the two environments are similar; The core work of establishing the artificial simulation environment test system is to solve the problems of simulation environment parameters (such as temperature, humidity, wetting time, cycle time, wind speed, etc.). However, the existing research has not reached a consensus on the test system and the basis, and the research results are difficult to compare quantitatively. On the basis of summarizing the existing research, this paper puts forward the design method of artificial simulation environment test system based on the similar internal micro-environment response of concrete, and based on this test system and the concrete chlorine salt erosion similarity criterion model, The similar relationship between the artificial simulation and the corrosion of the concrete in the natural environment is constructed. The contents of the study are as follows: (1) Based on the concept of the internal micro-environment of the concrete, the temperature/ humidity function spectrum of the natural environment and the temperature/ humidity response spectrum of the micro-environment in the concrete are established. The paper analyzes the similarities and differences between the environmental factors and the internal micro-environmental responses of the concrete, and discusses the correlation and application between the relative humidity and the water vapor density. The results show that the differences and differences between the micro-environment and the natural environment in the concrete mainly show that the fluctuation period is the same, the phase lag and the peak attenuation, and so on, the natural environment can not be considered as the internal micro-environment of the concrete. in that environment, the change rule of the natural environment and the humidity of the micro-environment inside the concrete can be better describe by using the form of water vapor density. (2) The internal micro-environmental temperature response model of concrete is set up by discussing the response of the internal micro-environment temperature of the concrete in the artificial environment. The results show that the micro-environmental response of the concrete in the artificial simulation environment is different from the natural environment due to the different mechanism of the environment, and the experimental results and theoretical models of the micro-environmental response in the concrete in the artificial simulation environment are different from those of the natural environment. (3) The surface factor model of concrete moisture transfer with temperature and wind speed parameters is established, and the numerical simulation method is used to study the wind speed to wet the concrete. The numerical simulation results show that if the wind speed and the critical drying time exceed the fixed value (the wind speed is about 3.0m/ s, the critical drying time is about 13h), the simulated environmental humidity can be equivalent to the interface humidity between the concrete and the environment; This is due to the amount of moisture transfer between the interior of the concrete, the surface of the concrete and the outside environment A similar artificial simulation based on the internal micro-environmental response of concrete is put forward. The design method of the environmental test system is established. By analyzing the internal micro-environmental response and the boundary conditions of the concrete, the artificial simulation environment test parameters (such as temperature, humidity, wetting time, drying time, circulating wind speed and chlorine salt solution) are established. the value basis and the range of the concentration, etc.) are taken as the basis and the range, and the artificial simulation test system parameter in the prior art is solved. The influence of the concrete water-cement ratio, the initial saturation of concrete and the humidity gradient on the dry-wet equilibrium time ratio and the depth of water influence is analyzed based on the water transfer model in the concrete surface layer, and the BET isothermal adsorption curve is used to solve the concrete. The results show that the ratio of dry and wet equilibrium time of concrete and the depth of water influence are established. The important indexes of the simulation test system are derived. (5) The model and the similar relation of the model and the similar relationship of the corrosion of the chlorine and salt in the environment of artificial simulation and natural chlorine salt are derived. and the chlorine salt is evaluated by using an artificial simulation test system and a research method through the establishment of a concrete chloride ion diffusion coefficient and a surface layer chloride ion convection zone depth model. The durability of the typical concrete structure in the environment is shown. The results show that the relationship between the chloride ion concentration and the elevation of the concrete surface and the distance between the sea and the sea is in accordance with the S curve, and the difference between the corrosion of the concrete and the chloride in the artificial simulation and the natural environment is mainly shown as the chloride ion content of the surface layer of the concrete and the chlorine separation. the depth and diffusion coefficient of the sub-convection zone; the specific artificial simulation environment test and the natural environment
【学位授予单位】：中南大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU375
[Abstract]:Abstract: The corrosion of the steel bar caused by the chloride ion is the main cause of the deterioration of the durability of the reinforced concrete structure in the chlorine salt environment, and the similar relation between the corrosion of the concrete and the chloride in the environment of artificial simulation and natural chlorine salt is established. It is of great significance to accurately predict the service life of the concrete structure in the chlorine salt environment and to evaluate its durability. In order to establish a similar relationship between the corrosion of the concrete and the chloride in the environment of artificial simulation and natural chlorine salt, it is necessary to establish a suitable artificial simulation environment test system to ensure that the corrosion process and mechanism of the concrete chlorosalt in the two environments are similar; The core work of establishing the artificial simulation environment test system is to solve the problems of simulation environment parameters (such as temperature, humidity, wetting time, cycle time, wind speed, etc.). However, the existing research has not reached a consensus on the test system and the basis, and the research results are difficult to compare quantitatively. On the basis of summarizing the existing research, this paper puts forward the design method of artificial simulation environment test system based on the similar internal micro-environment response of concrete, and based on this test system and the concrete chlorine salt erosion similarity criterion model, The similar relationship between the artificial simulation and the corrosion of the concrete in the natural environment is constructed. The contents of the study are as follows: (1) Based on the concept of the internal micro-environment of the concrete, the temperature/ humidity function spectrum of the natural environment and the temperature/ humidity response spectrum of the micro-environment in the concrete are established. The paper analyzes the similarities and differences between the environmental factors and the internal micro-environmental responses of the concrete, and discusses the correlation and application between the relative humidity and the water vapor density. The results show that the differences and differences between the micro-environment and the natural environment in the concrete mainly show that the fluctuation period is the same, the phase lag and the peak attenuation, and so on, the natural environment can not be considered as the internal micro-environment of the concrete. in that environment, the change rule of the natural environment and the humidity of the micro-environment inside the concrete can be better describe by using the form of water vapor density. (2) The internal micro-environmental temperature response model of concrete is set up by discussing the response of the internal micro-environment temperature of the concrete in the artificial environment. The results show that the micro-environmental response of the concrete in the artificial simulation environment is different from the natural environment due to the different mechanism of the environment, and the experimental results and theoretical models of the micro-environmental response in the concrete in the artificial simulation environment are different from those of the natural environment. (3) The surface factor model of concrete moisture transfer with temperature and wind speed parameters is established, and the numerical simulation method is used to study the wind speed to wet the concrete. The numerical simulation results show that if the wind speed and the critical drying time exceed the fixed value (the wind speed is about 3.0m/ s, the critical drying time is about 13h), the simulated environmental humidity can be equivalent to the interface humidity between the concrete and the environment; This is due to the amount of moisture transfer between the interior of the concrete, the surface of the concrete and the outside environment A similar artificial simulation based on the internal micro-environmental response of concrete is put forward. The design method of the environmental test system is established. By analyzing the internal micro-environmental response and the boundary conditions of the concrete, the artificial simulation environment test parameters (such as temperature, humidity, wetting time, drying time, circulating wind speed and chlorine salt solution) are established. the value basis and the range of the concentration, etc.) are taken as the basis and the range, and the artificial simulation test system parameter in the prior art is solved. The influence of the concrete water-cement ratio, the initial saturation of concrete and the humidity gradient on the dry-wet equilibrium time ratio and the depth of water influence is analyzed based on the water transfer model in the concrete surface layer, and the BET isothermal adsorption curve is used to solve the concrete. The results show that the ratio of dry and wet equilibrium time of concrete and the depth of water influence are established. The important indexes of the simulation test system are derived. (5) The model and the similar relation of the model and the similar relationship of the corrosion of the chlorine and salt in the environment of artificial simulation and natural chlorine salt are derived. and the chlorine salt is evaluated by using an artificial simulation test system and a research method through the establishment of a concrete chloride ion diffusion coefficient and a surface layer chloride ion convection zone depth model. The durability of the typical concrete structure in the environment is shown. The results show that the relationship between the chloride ion concentration and the elevation of the concrete surface and the distance between the sea and the sea is in accordance with the S curve, and the difference between the corrosion of the concrete and the chloride in the artificial simulation and the natural environment is mainly shown as the chloride ion content of the surface layer of the concrete and the chlorine separation. the depth and diffusion coefficient of the sub-convection zone; the specific artificial simulation environment test and the natural environment
【学位授予单位】：中南大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU375
【参考文献】
相关期刊论文 前10条
1 李果,刘涛,费金新,饶丹,郭兵兵;干湿循环混凝土内钢筋腐蚀加速效应机理的研究[J];四川建筑科学研究;2005年05期
2 姬永生;司维;袁迎曙;刘先观;柏霞;;混凝土孔隙水饱和度的试验研究[J];四川建筑科学研究;2010年01期
3 龙广成;邢锋;余志武;谢友均;;自然扩散条件下SO_4~(2-)、Cl~-在砂浆中的沉积特性[J];材料科学与工程学报;2008年05期
4 余红发;孙伟;;混凝土氯离子扩散理论模型[J];东南大学学报(自然科学版);2006年S2期
5 卫军;余t，
本文编号：2317528
本文链接：https://www.wllwen.com/kejilunwen/sgjslw/2317528.html
