人工模擬和自然氯鹽環(huán)境下混凝土氯鹽侵蝕相似性研究
發(fā)布時間：2018-11-07 20:46
【摘要】：摘要：氯離子引起鋼筋銹蝕是導(dǎo)致氯鹽環(huán)境中鋼筋混凝土結(jié)構(gòu)耐久性退化的主因；建立人工模擬和自然氯鹽環(huán)境中混凝土氯鹽侵蝕的相似關(guān)系,對準確地預(yù)測氯鹽環(huán)境中混凝土結(jié)構(gòu)的使用壽命和評估其耐久性具有重要意義。若要建立人工模擬和自然氯鹽環(huán)境中混凝土氯鹽侵蝕的相似關(guān)系,前提條件則是先確立適宜的人工模擬環(huán)境試驗制度以保證兩種環(huán)境中混凝土氯鹽侵蝕過程和機理的相似；而確立人工模擬環(huán)境試驗制度的核心工作則是解決模擬環(huán)境參數(shù)(如溫度、濕度、潤濕時間、循環(huán)時間和風(fēng)速等)取值依據(jù)和范圍問題。然而,現(xiàn)有研究在試驗制度和依據(jù)方面尚未達成共識,研究成果難以定量對比。本文在總結(jié)已有研究的基礎(chǔ)上,提出了基于混凝土內(nèi)部微環(huán)境響應(yīng)相似的人工模擬環(huán)境試驗制度的設(shè)計方法；基于該試驗制度和混凝土氯鹽侵蝕相似準則模型,構(gòu)筑了人工模擬和自然環(huán)境中混凝土氯鹽侵蝕相似關(guān)系。研究內(nèi)容如下： (1)基于混凝土內(nèi)部微環(huán)境層次理念,建立了分段形式的自然環(huán)境溫/濕度作用譜和混凝土內(nèi)微環(huán)境溫/濕度響應(yīng)譜模型。摒除了將自然環(huán)境直接等效為混凝土內(nèi)微環(huán)境觀念的不足,分析了環(huán)境因素作用和混凝土內(nèi)部微環(huán)境響應(yīng)間的異同,探討了濕度采用相對濕度與水汽密度表達形式間的關(guān)聯(lián)和適用范圍。研究結(jié)果表明：混凝土內(nèi)微環(huán)境與自然環(huán)境間的異同主要表現(xiàn)為波動周期相等、相位滯后和峰值衰減等方面,不可將自然環(huán)境簡單地視為混凝土內(nèi)部微環(huán)境；采用水汽密度表達形式可更好地描述自然環(huán)境濕度變化規(guī)律和表征混凝土內(nèi)部微環(huán)境濕度特征。 (2)通過探討人工模擬環(huán)境中混凝土內(nèi)部微環(huán)境溫度響應(yīng),建立了混凝土內(nèi)部微環(huán)境溫度響應(yīng)模型,并提出了求解模型數(shù)值解的新方法。分析表明：因環(huán)境作用機制的不同使得人工模擬環(huán)境中混凝土內(nèi)微環(huán)境響應(yīng)規(guī)律有別于自然環(huán)境,人工模擬環(huán)境中混凝土內(nèi)微環(huán)境響應(yīng)實測結(jié)果與理論模型曲線吻合較佳。 (3)建立了含溫度和風(fēng)速參數(shù)的混凝土水分傳輸表面因子模型,并采用數(shù)值模擬法探討了風(fēng)速對混凝土內(nèi)濕度分布狀態(tài)的影響。數(shù)值模擬結(jié)果表明：若風(fēng)速和臨界干燥時間超過定值(風(fēng)速約為3.0m/s,臨界干燥時間約為13h),則可將模擬環(huán)境濕度等效為混凝土與環(huán)境間的界面濕度；這是因混凝土內(nèi)部、混凝土表層和外界環(huán)境間的水分傳輸量達到平衡態(tài)造成的。 (4)提出了基于混凝土內(nèi)部微環(huán)境響應(yīng)相似的人工模擬環(huán)境試驗制度的設(shè)計方法。通過分析混凝土內(nèi)部微環(huán)境響應(yīng)規(guī)律和邊界條件,確立了人工模擬環(huán)境試驗參數(shù)(如溫度、濕度、潤濕時間、干燥時間、循環(huán)風(fēng)速和氯鹽溶液濃度等)取值依據(jù)和范圍,解決了現(xiàn)有研究中人工模擬試驗制度參數(shù)取值依據(jù)不充分的難題�；诨炷帘韺觾�(nèi)水分傳輸模型,分析了混凝土水灰比、混凝土初始飽和度和濕度梯度對干濕平衡時間比和水分影響深度的影響；還提出了采用BET等溫吸附曲線求解混凝土內(nèi)水分特征曲線的新途徑。結(jié)果表明：混凝土干濕平衡時間比和水分影響深度是確立人工模擬試驗制度的重要指標(biāo)。 (5)推導(dǎo)了人工模擬和自然氯鹽環(huán)境混凝土氯鹽侵蝕相似準則模型和相似關(guān)系,并為實際工程測試數(shù)據(jù)所驗證。通過建立混凝土氯離子擴散系數(shù)和表層氯離子對流區(qū)深度模型,利用人工模擬試驗制度和研究方法評估了氯鹽環(huán)境中典型混凝土結(jié)構(gòu)的耐久性。結(jié)果表明：混凝土表層的氯離子濃度與高程和距海距離間的關(guān)系均符合S曲線,人工模擬和自然環(huán)境中混凝土氯鹽侵蝕間的差異主要表現(xiàn)為混凝土表層氯離子含量、氯離子對流區(qū)深度和擴散系數(shù)等方面；特定的人工模擬環(huán)境試驗和自然環(huán)境中混凝土氯鹽侵蝕的相似率為定值。
[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
【學(xué)位授予單位】：中南大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2013
【分類號】：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
【學(xué)位授予單位】：中南大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2013
【分類號】：TU375
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