抗氯鹽高性能混凝土抗氯離子滲透性能時變規(guī)律實驗研究
發(fā)布時間：2019-01-07 19:41
【摘要】：抗氯鹽高性能混凝土是采用低水膠比和優(yōu)質礦物摻合料等技術措施配制的高性能混凝土，由于它具有優(yōu)良的抗氯離子滲透性能，采用這種技術現(xiàn)已成為解決氯鹽環(huán)境中混凝土結構耐久性問題的主要措施。隨著沿海經(jīng)濟的騰飛，抗氯鹽高性能混凝土具有廣闊的發(fā)展前景和應用價值，但調研發(fā)現(xiàn)抗氯鹽高性能混凝土的研究還存在一些亟待解決的問題，例如抗氯鹽高性能混凝土熱物理性能研究很少，缺乏可利用的實測數(shù)據(jù)，由此是否導致混凝土開裂風險增加的問題還不明確；我國不同規(guī)范所用混凝土抗氯離子滲透性能的評定體系存在差異，造成不同規(guī)范評估混凝土抗氯離子滲透性能可能得出不同結論；混凝土結構壽命預測研究中氯離子擴散模型所用的齡期系數(shù)取值存在較大差異，缺少與我國混凝土原材料相適應的齡期系數(shù)取值方法等。 針對這些問題，本文進行了大量的試驗研究工作，實測了抗氯鹽高性能混凝土熱物理性能基本參數(shù)，采用電量綜合法研究了混凝土一年內齡期抗氯離子滲透性能，并通過五年齡期自然擴散法和電量綜合法試驗對比研究了混凝土抗氯離子滲透性能的時變規(guī)律。在本文研究情況下，可得出主要結論如下： （1）摻入大量礦物摻合料可有效降低混凝土的絕熱溫升值，礦物摻合料摻量、種類及比例對混凝土導熱、導溫系數(shù)和比熱容影響較小�？孤塞}高性能混凝土導熱、導溫和比熱性能可采用普通混凝土計算方法計算。 （2）電加速試驗采用56天齡期混凝土氯離子擴散系數(shù)評價混凝土抗氯離子滲透性能結果較為合適，由于電量值和氯離子擴散系數(shù)有一定相關性，可用本文劃分的混凝土電量值和氯離子擴散系數(shù)雙指標體系評判混凝土抗氯離子滲透性能等級。 （3）混凝土抗氯離子滲透性能隨齡期的延長而顯著提高，氯離子擴散系數(shù)符合指數(shù)衰減規(guī)律，其齡期系數(shù)與混凝土水膠比和礦物摻合料摻量等因素有關，可用本文所得公式計算水下環(huán)境混凝土齡期系數(shù)。延長養(yǎng)護齡期可有效降低混凝土初始氯離子擴散系數(shù)，，但對混凝土氯離子擴散時變規(guī)律幾乎沒有影響。 （4）基于電加速方法前兩年齡期試驗結果得到混凝土氯離子擴散系數(shù)時變規(guī)律與自然擴散法試驗結果基本保持一致，可真實有效的反映混凝土抗氯離子滲透性能時變規(guī)律。為增加壽命預測的準確度，混凝土結構使用壽命預測建議采用一年齡期或更長齡期工程實測氯離子擴散系數(shù)作為預測起點。
[Abstract]:Chlorine salt resistant high performance concrete is a kind of high performance concrete prepared by low water / binder ratio and high quality mineral admixture. This technique has become the main measure to solve the durability problem of concrete structure in chloride environment. With the rapid development of coastal economy, anti-chlorine-resistant high performance concrete has broad development prospects and application value, but the investigation and research found that there are still some problems to be solved urgently in the research of chloride resistant high performance concrete. For example, there are few researches on the thermophysical properties of chloride resistant high performance concrete, and it is not clear whether it will lead to the increase of cracking risk of concrete. There are differences in the evaluation system of chloride ion permeability of concrete used in different codes in China, which may lead to different conclusions in evaluating the chloride ion permeability of concrete under different specifications. In the study of life prediction of concrete structures, there are great differences in the age coefficients used in the chloride diffusion model, and there is a lack of the age coefficient method suitable for the raw materials of concrete in our country, and so on. In order to solve these problems, a great deal of experimental work has been carried out in this paper, and the basic parameters of the thermophysical properties of high performance concrete resistant to chloride salt have been measured, and the resistance to chloride ion permeability of concrete in one year has been studied by the method of electricity quantity synthesis. The time-varying law of chloride permeation resistance of concrete was studied by comparing the natural diffusion method of five years and the electric quantity synthesis method. In this paper, the main conclusions can be drawn as follows: (1) adding a large amount of mineral admixtures can effectively reduce the adiabatic temperature appreciation of concrete. The influence of temperature conductivity and specific heat capacity is small. The thermal conductivity and specific heat transfer of chloride resistant high performance concrete can be calculated by ordinary concrete calculation method. (2) in the electric accelerated test, the chloride ion diffusion coefficient of 56 days old concrete is suitable to evaluate the chloride ion permeability of concrete, because of the correlation between the electricity quantity and the chloride ion diffusion coefficient. The grade of chloride permeation resistance of concrete can be evaluated by the two-index system of concrete electric quantity and chloride ion diffusion coefficient which is divided in this paper. (3) the permeability of concrete to chloride ion increases with the increase of age, and the diffusion coefficient of chloride ion accords with the law of exponential attenuation, and its age coefficient is related to the factors such as the ratio of concrete to binder and the amount of mineral admixture, etc. The age coefficient of underwater environment concrete can be calculated by the formula obtained in this paper. Prolonging the curing age can effectively reduce the initial chloride diffusion coefficient of concrete, but have little effect on the time-varying rule of chloride ion diffusion in concrete. (4) based on the experimental results of the first two years of the electric acceleration method, the time-varying law of chloride diffusion coefficient of concrete is basically consistent with that of the natural diffusion method, which can reflect the time-varying law of chloride ion permeation resistance of concrete. In order to increase the accuracy of life prediction, it is suggested that the measured chloride diffusion coefficient of concrete structures should be used as the starting point for the prediction of the service life of concrete structures.
【學位授予單位】：華南理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TU528
[Abstract]:Chlorine salt resistant high performance concrete is a kind of high performance concrete prepared by low water / binder ratio and high quality mineral admixture. This technique has become the main measure to solve the durability problem of concrete structure in chloride environment. With the rapid development of coastal economy, anti-chlorine-resistant high performance concrete has broad development prospects and application value, but the investigation and research found that there are still some problems to be solved urgently in the research of chloride resistant high performance concrete. For example, there are few researches on the thermophysical properties of chloride resistant high performance concrete, and it is not clear whether it will lead to the increase of cracking risk of concrete. There are differences in the evaluation system of chloride ion permeability of concrete used in different codes in China, which may lead to different conclusions in evaluating the chloride ion permeability of concrete under different specifications. In the study of life prediction of concrete structures, there are great differences in the age coefficients used in the chloride diffusion model, and there is a lack of the age coefficient method suitable for the raw materials of concrete in our country, and so on. In order to solve these problems, a great deal of experimental work has been carried out in this paper, and the basic parameters of the thermophysical properties of high performance concrete resistant to chloride salt have been measured, and the resistance to chloride ion permeability of concrete in one year has been studied by the method of electricity quantity synthesis. The time-varying law of chloride permeation resistance of concrete was studied by comparing the natural diffusion method of five years and the electric quantity synthesis method. In this paper, the main conclusions can be drawn as follows: (1) adding a large amount of mineral admixtures can effectively reduce the adiabatic temperature appreciation of concrete. The influence of temperature conductivity and specific heat capacity is small. The thermal conductivity and specific heat transfer of chloride resistant high performance concrete can be calculated by ordinary concrete calculation method. (2) in the electric accelerated test, the chloride ion diffusion coefficient of 56 days old concrete is suitable to evaluate the chloride ion permeability of concrete, because of the correlation between the electricity quantity and the chloride ion diffusion coefficient. The grade of chloride permeation resistance of concrete can be evaluated by the two-index system of concrete electric quantity and chloride ion diffusion coefficient which is divided in this paper. (3) the permeability of concrete to chloride ion increases with the increase of age, and the diffusion coefficient of chloride ion accords with the law of exponential attenuation, and its age coefficient is related to the factors such as the ratio of concrete to binder and the amount of mineral admixture, etc. The age coefficient of underwater environment concrete can be calculated by the formula obtained in this paper. Prolonging the curing age can effectively reduce the initial chloride diffusion coefficient of concrete, but have little effect on the time-varying rule of chloride ion diffusion in concrete. (4) based on the experimental results of the first two years of the electric acceleration method, the time-varying law of chloride diffusion coefficient of concrete is basically consistent with that of the natural diffusion method, which can reflect the time-varying law of chloride ion permeation resistance of concrete. In order to increase the accuracy of life prediction, it is suggested that the measured chloride diffusion coefficient of concrete structures should be used as the starting point for the prediction of the service life of concrete structures.
【學位授予單位】：華南理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TU528
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中國期刊全文數(shù)據(jù)庫 前10條
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