本文選題：混凝土 + 耐久性��； 參考：《廣西大學(xué)》2017年碩士論文

【摘要】：在海洋氯化物環(huán)境下,混凝土結(jié)構(gòu)的耐久性劣化問題主要是由于外部腐蝕性氯離子侵入混凝土內(nèi)部誘導(dǎo)鋼筋發(fā)生銹蝕造成的。由于氯離子擴散系數(shù)是決定氯離子在混凝土中傳輸快慢的重要參數(shù)之一,所以直接影響混凝土結(jié)構(gòu)的服役壽命。氯離子擴散系數(shù)不僅受材料參數(shù)和環(huán)境條件的影響,具有顯著的隨機性,而且隨著混凝土齡期的增加而逐漸降低,呈現(xiàn)顯著的時變特性。因此,有必要綜合考慮環(huán)境條件、材料參數(shù)和時變特性的影響,建立混凝土中氯離子擴散系數(shù)的概率預(yù)測模型,進而開展混凝土結(jié)構(gòu)的概率服役壽命預(yù)測。鑒于此,本文分別基于室內(nèi)加速試驗數(shù)據(jù)和自然暴露試驗數(shù)據(jù),建立了室內(nèi)加速試驗和自然暴露條件下混凝土中氯離子擴散系數(shù)的概率預(yù)測模型,在此基礎(chǔ)上提出了海洋氯化物環(huán)境下混凝土結(jié)構(gòu)的概率服役壽命預(yù)測方法。主要研究內(nèi)容包括:(1)基于所收集的295組利用室內(nèi)加速試驗(RCM法)測試的氯離子擴散系數(shù)的試驗數(shù)據(jù),定量分析了水膠比、粉煤灰摻量、礦粉摻量等因素對氯離子擴散系數(shù)的影響規(guī)律,并利用逐步回歸分析法遴選顯著變量,建立了混凝土中氯離子擴散系數(shù)的確定性預(yù)測模型,進而綜合考慮主觀不確定性和客觀不確定性的影響,結(jié)合貝葉斯理論和馬爾科夫鏈蒙特卡洛法,建立了室內(nèi)加速試驗條件下混凝土中氯離子擴散系數(shù)的概率預(yù)測模型。(2)基于所收集的913組利用自然暴露試驗數(shù)據(jù)擬合確定的氯離子擴散系數(shù)數(shù)據(jù),綜合考慮材料參數(shù)和環(huán)境條件的影響,建立了海洋潮汐區(qū)、浪濺區(qū)、大氣區(qū)和水下區(qū)環(huán)境條件下混凝土中氯離子擴散系數(shù)與暴露時間、配合比參數(shù)(水膠比、礦物摻合料d{量)之間的確定性關(guān)系模型,進而綜合考慮主觀不確定性和客觀不確定性的影響,結(jié)合貝葉斯理論和馬爾科夫鏈蒙特卡洛法,建立了海洋氯化物環(huán)境下混凝土中氯離子擴散系數(shù)的概率預(yù)測模型,并建立了室內(nèi)加速試驗條件與自然暴露條件下混凝土中氯離子擴散系數(shù)之間的轉(zhuǎn)換關(guān)系。(3)基于氯離子擴散系數(shù)的概率預(yù)測模型,結(jié)合混凝土中鋼筋銹蝕(誘導(dǎo)期)的服役壽命預(yù)測模型,提出了海洋氯化物環(huán)境下混凝土結(jié)構(gòu)的概率服役壽命預(yù)測方法,并定量分析了環(huán)境條件(如潮汐區(qū)、浪濺區(qū)、大氣區(qū)和水下區(qū))、材料參數(shù)(如水膠比和礦物摻合料)、混凝土保護層厚度等重要因素對海洋氯化物環(huán)境下混凝土結(jié)構(gòu)概率服役壽命的影響規(guī)律。
[Abstract]:In marine chloride environment, the deterioration of durability of concrete structures is mainly caused by the corrosion of steel bars induced by external corrosive chloride ions intruding into the concrete. The chloride diffusion coefficient is one of the important parameters to determine the speed of chloride ion transport in concrete, so it directly affects the service life of concrete structure. The chloride diffusion coefficient is not only affected by material parameters and environmental conditions, but also decreases with the increase of concrete age. Therefore, it is necessary to establish a probabilistic prediction model of chloride diffusion coefficient in concrete considering the influence of environmental conditions, material parameters and time-varying characteristics, and then to predict the probabilistic service life of concrete structures. In view of this, based on indoor accelerated test data and natural exposure test data, the probabilistic prediction model of chloride diffusion coefficient in concrete under indoor accelerated test and natural exposure condition is established in this paper. On this basis, the probabilistic service life prediction method of concrete structures under marine chloride environment is proposed. The main contents are as follows: (1) based on the data collected from 295 groups of chlorine ion diffusion coefficient measured by indoor accelerated test (RCM), the water binder ratio and fly ash content are quantitatively analyzed. The influence of mineral powder content on chloride diffusion coefficient is studied. The deterministic prediction model of chloride ion diffusion coefficient in concrete is established by using stepwise regression analysis to select significant variables. Furthermore, considering the influence of subjective uncertainty and objective uncertainty, combined with Bayesian theory and Markov chain Monte Carlo method, A probabilistic prediction model of chloride diffusion coefficient in concrete under accelerated indoor test was established. (2) based on 913 groups of data obtained from natural exposure test, the chloride diffusion coefficient was fitted. Considering the influence of material parameters and environmental conditions, the chloride diffusion coefficient, exposure time and mixing ratio parameters (water / binder ratio) of concrete in marine tidal zone, splash zone, large air zone and underwater area were established. The deterministic relation model between mineral admixtures d {quantity], then considering the influence of subjective uncertainty and objective uncertainty, combined with Bayesian theory and Markov chain Monte Carlo method. The probabilistic prediction model of chloride diffusion coefficient in concrete under marine chloride environment is established. The conversion relationship between the indoor accelerated test conditions and the chloride diffusion coefficient in the concrete under natural exposure is established. (3) the probability prediction model based on the chloride ion diffusion coefficient is presented. The probabilistic service life prediction method of concrete structures in marine chloride environment is proposed, and the quantitative analysis of environmental conditions (such as tidal zone, wave splash zone) is also given, combining with the prediction model of service life of steel bar corrosion (induced period) in concrete, and the probabilistic service life prediction method of concrete structure under marine chloride environment is presented. The influence of material parameters (such as water-binder ratio and mineral admixture) and the thickness of concrete cover on the probabilistic service life of concrete structure in marine chloride environment.
【學(xué)位授予單位】：廣西大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TU528

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