吉林省西部地區(qū)鹽漬土環(huán)境下混凝土耐久性研究
發(fā)布時間：2018-12-21 12:52
【摘要】：混凝土耐久性問題是混凝土材料科學領域的一項重要研究課題。隨著混凝土的廣泛應用，使用環(huán)境的日益惡化，混凝土工程受環(huán)境侵蝕的危害性也日益增加，即環(huán)境條件的嚴酷程度決定了混凝土結(jié)構(gòu)工程壽命的長短。在國家自然科學基金項目“東北季凍區(qū)路基水份遷移的微觀機理研究”（No.406721780）和國家自然科學基金項目“不同氣候帶幾種表生特殊土的形成環(huán)境及演化趨勢”（No.40911120044）、博士點基金“干濕凍融循環(huán)對吉林西部分散土的影響及機理研究”（No.20120061110054）資助下，本文針對吉林西部鹽漬土分布區(qū)內(nèi)的混凝土工程為研究對象，，結(jié)合吉林西部地區(qū)的氣候條件與土壤環(huán)境等因素，開展了混凝土耐久性的研究工作，主要揭示鹽蝕、干濕、凍融等單一或多重因素作用下混凝土性能的衰變規(guī)律，進行不同環(huán)境因素或土壤情況下混凝土破壞機理分析與評價，以及混凝土耐久性的諸多影響因素與其質(zhì)量或動彈性模量的關聯(lián)度分析，以減少季凍區(qū)鹽堿土對混凝土工程耐久與安全的潛在威脅，并進一步完善混凝土耐久性研究的理論體系。 吉林省大安市是松嫩平原土壤鹽漬化最嚴重的地區(qū)之一，以蘇打鹽漬土為主，境內(nèi)的土壤及地表水中的易溶鹽分量相似。針對大安鹽漬土區(qū)的自然環(huán)境特點，模擬實際工程的環(huán)境條件設計了四種試驗工況，即鹽浸、鹽蝕-干濕、鹽蝕-凍融、鹽蝕-凍融-干濕試驗；并根據(jù)大安春季土壤中主要易溶鹽的種類與含量，配制了不同濃度的復合鹽侵蝕溶液，根據(jù)復合鹽中的各種易溶鹽分別配置了單鹽侵蝕溶液進行對比試驗；制備五種不同配合比的基準混凝土、粉煤灰混凝土、引氣混凝土試件，進行了以下四組試驗：混凝土的復合鹽或單鹽溶液長期浸泡試驗、復合鹽或單鹽-干濕循環(huán)試驗、復合鹽或單鹽-凍融循環(huán)試驗、復合鹽或單鹽-凍融-干濕循環(huán)試驗，以質(zhì)量與動彈性模量的變化作為混凝土耐久性能的評價指標；同時，通過物理、電鏡掃描及超聲波等手段進行混凝土在各種試驗工況下的性能研究，包括混凝土的破壞規(guī)律、破壞機理分析、宏觀現(xiàn)象、微觀結(jié)構(gòu)、質(zhì)量損失與動彈性模量衰減規(guī)律、以及影響因素等。在以上試驗數(shù)據(jù)的基礎上，利用灰關聯(lián)度法和粗糙集理論對浸泡時間、凍融循環(huán)次數(shù)、干濕循環(huán)次數(shù)、凍融-干濕次數(shù)、復合鹽濃度、含氣量、粉煤灰摻量7個影響因素分別與混凝土的質(zhì)量損失率、相對動彈性模量的關系進行分析，確定各影響因素對混凝土耐久性影響程度的大小，計算權(quán)重，并進行不同環(huán)境條件下混凝土動彈性模量的衰減規(guī)律評價，從而對吉林省西部地區(qū)鹽漬土環(huán)境下混凝土耐久性進行深入研究。
[Abstract]:The durability of concrete is an important research topic in the field of concrete material science. With the extensive application of concrete and the deterioration of the environment, the harm of environmental erosion of concrete engineering is increasing day by day, that is, the severity of environmental conditions determines the length of life of concrete structure engineering. In the project of National Natural Science Foundation of China, "microscopic mechanism of subgrade water migration in northeast seasonal frozen region" (No.406721780) and "formation environment and evolution trend of several kinds of supergene special soil in different climatic zones" (No.40911120044), the project of National Natural Science Foundation of China (NSFC) is presented. The effect and Mechanism of Dry-Wet Freeze-thaw cycle on dispersed soils in Western Jilin Province (No.20120061110054) is supported by the doctoral Program Foundation. This paper focuses on concrete engineering in the saline soil distribution area of western Jilin Province. Combined with the climatic conditions and soil environment in the west of Jilin Province, the durability of concrete is studied, which mainly reveals the decay law of concrete performance under the action of single or multiple factors, such as salt erosion, drying and wet, freezing and thawing, etc. The failure mechanism of concrete is analyzed and evaluated under different environmental factors or soil conditions, and the correlation degree between many factors affecting the durability of concrete and its quality or dynamic modulus of elasticity is analyzed. In order to reduce the potential threat to durability and safety of concrete engineering caused by saline-alkali soil in seasonally frozen area, and further improve the theoretical system of concrete durability research. Da'an City of Jilin Province is one of the most serious soil salinization areas in Songnen Plain. Soda saline soil is the main soil and the soluble salt content in soil and surface water is similar. According to the characteristics of the natural environment in the saline soil area of Da'an, four test conditions were designed to simulate the environmental conditions of the actual engineering, namely, salt leaching, salt erosion-dry-wet, salt-corrosion-freeze-thaw and dry-wet test. According to the types and contents of the main soluble salts in the spring soil of Da'an, different concentrations of complex salt erosion solution were prepared, and the single salt erosion solution was allocated separately according to the various soluble salts in the compound salt. Five kinds of reference concrete, fly ash concrete and air-entrained concrete specimens with different mix ratios were prepared. The following four groups of tests were carried out: the long-term immersion test of the compound salt or single salt solution, the test of the composite salt or the single salt-dry and wet cycle test, Compound salt or single salt-freeze-thaw cycle test, compound salt or single salt-freeze-thawing-dry and wet cycle test, take the change of mass and dynamic elastic modulus as the evaluation index of concrete durability. At the same time, the performance of concrete under various test conditions is studied by means of physics, scanning electron microscope and ultrasonic wave, including the failure law of concrete, the analysis of failure mechanism, the macroscopic phenomenon, the microstructure of concrete, and so on. Mass loss and dynamic elastic modulus attenuation, and influencing factors, etc. On the basis of the above experimental data, the soaking time, freeze-thaw cycle times, dry-wet cycles, freeze-thawing-dry-wet times, complex salt concentration and gas content were analyzed by grey correlation degree method and rough set theory. The relationship between the weight loss rate of concrete and the relative dynamic elastic modulus of concrete is analyzed, and the influence degree of each factor on the durability of concrete is determined and the weight is calculated. The attenuation law of dynamic elastic modulus of concrete under different environmental conditions was evaluated, and the durability of concrete under saline soil environment in western Jilin Province was studied in depth.
【學位授予單位】：吉林大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：TU528
本文編號：2388934
[Abstract]:The durability of concrete is an important research topic in the field of concrete material science. With the extensive application of concrete and the deterioration of the environment, the harm of environmental erosion of concrete engineering is increasing day by day, that is, the severity of environmental conditions determines the length of life of concrete structure engineering. In the project of National Natural Science Foundation of China, "microscopic mechanism of subgrade water migration in northeast seasonal frozen region" (No.406721780) and "formation environment and evolution trend of several kinds of supergene special soil in different climatic zones" (No.40911120044), the project of National Natural Science Foundation of China (NSFC) is presented. The effect and Mechanism of Dry-Wet Freeze-thaw cycle on dispersed soils in Western Jilin Province (No.20120061110054) is supported by the doctoral Program Foundation. This paper focuses on concrete engineering in the saline soil distribution area of western Jilin Province. Combined with the climatic conditions and soil environment in the west of Jilin Province, the durability of concrete is studied, which mainly reveals the decay law of concrete performance under the action of single or multiple factors, such as salt erosion, drying and wet, freezing and thawing, etc. The failure mechanism of concrete is analyzed and evaluated under different environmental factors or soil conditions, and the correlation degree between many factors affecting the durability of concrete and its quality or dynamic modulus of elasticity is analyzed. In order to reduce the potential threat to durability and safety of concrete engineering caused by saline-alkali soil in seasonally frozen area, and further improve the theoretical system of concrete durability research. Da'an City of Jilin Province is one of the most serious soil salinization areas in Songnen Plain. Soda saline soil is the main soil and the soluble salt content in soil and surface water is similar. According to the characteristics of the natural environment in the saline soil area of Da'an, four test conditions were designed to simulate the environmental conditions of the actual engineering, namely, salt leaching, salt erosion-dry-wet, salt-corrosion-freeze-thaw and dry-wet test. According to the types and contents of the main soluble salts in the spring soil of Da'an, different concentrations of complex salt erosion solution were prepared, and the single salt erosion solution was allocated separately according to the various soluble salts in the compound salt. Five kinds of reference concrete, fly ash concrete and air-entrained concrete specimens with different mix ratios were prepared. The following four groups of tests were carried out: the long-term immersion test of the compound salt or single salt solution, the test of the composite salt or the single salt-dry and wet cycle test, Compound salt or single salt-freeze-thaw cycle test, compound salt or single salt-freeze-thawing-dry and wet cycle test, take the change of mass and dynamic elastic modulus as the evaluation index of concrete durability. At the same time, the performance of concrete under various test conditions is studied by means of physics, scanning electron microscope and ultrasonic wave, including the failure law of concrete, the analysis of failure mechanism, the macroscopic phenomenon, the microstructure of concrete, and so on. Mass loss and dynamic elastic modulus attenuation, and influencing factors, etc. On the basis of the above experimental data, the soaking time, freeze-thaw cycle times, dry-wet cycles, freeze-thawing-dry-wet times, complex salt concentration and gas content were analyzed by grey correlation degree method and rough set theory. The relationship between the weight loss rate of concrete and the relative dynamic elastic modulus of concrete is analyzed, and the influence degree of each factor on the durability of concrete is determined and the weight is calculated. The attenuation law of dynamic elastic modulus of concrete under different environmental conditions was evaluated, and the durability of concrete under saline soil environment in western Jilin Province was studied in depth.
【學位授予單位】：吉林大學
【學位級別】：博士
【學位授予年份】：2013
【分類號】：TU528
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