本文關(guān)鍵詞： 除冰鹽 質(zhì)量損失率 相對(duì)動(dòng)彈性模量 最大抗凍融次數(shù)　出處：《內(nèi)蒙古科技大學(xué)》2014年碩士論文　論文類(lèi)型：學(xué)位論文

【摘要】：基礎(chǔ)設(shè)施建設(shè)大力發(fā)展的今天，混凝土在公路、橋梁、機(jī)場(chǎng)、碼頭、建筑工程等方面得到廣泛應(yīng)用。為了保證冬季交通的正常運(yùn)營(yíng)，融雪劑(除冰鹽)被大量使用，目前市場(chǎng)上的除冰鹽種類(lèi)較多，有NaCl、CaCl2、Ca(COOH)2、Mg(COOH)2、乙二醇等。不同除冰鹽對(duì)道路混凝土的破壞程度不同，侵蝕機(jī)理不同，對(duì)生態(tài)環(huán)境的污染程度也不同，因此研究不同除冰鹽環(huán)境下混凝土的抗凍耐久性具有重要意義。 本文通過(guò)普通混凝土快速凍融試驗(yàn)方法，分析不同鹽溶液(NaCl、CaCl2、CMA、Na2SO4)及其不同濃度(0%、3%、6%、12%、25%)對(duì)混凝土抗凍性的影響，得出鹽凍環(huán)境下混凝土的質(zhì)量損失、相對(duì)動(dòng)彈性模量和混凝土立方體抗壓強(qiáng)度的變化規(guī)律。 在NaCl鹽凍環(huán)境下，混凝土試件隨著凍融次數(shù)的增加，試塊表面剝濁程度逐漸加深，相對(duì)動(dòng)彈性模量、立方體抗壓強(qiáng)度逐漸下降。3%NaCl鹽凍的試塊破壞最為嚴(yán)重，凍融100次后質(zhì)量損失達(dá)7.55%，相對(duì)動(dòng)彈性模量為13.34%，混凝土立方體抗壓強(qiáng)度下降了60%。在NaCl和CaCl2鹽凍環(huán)境下混凝土耐久性相似，CaCl2鹽凍對(duì)混凝土的侵蝕較��；其次，不同濃度的CMA在同一凍融次數(shù)下,混凝土的狀態(tài)由好到差排列為：25%CMA＞12%CMA＞6%CMA＞3%CMA；再次，Na2SO4不易溶于水，鹽凍僅50次，，相對(duì)動(dòng)彈性模量下降到60%以下。鹽凍100次后混凝土粗骨料暴露，質(zhì)量損失急速增加，相對(duì)動(dòng)彈性模量?jī)H為20%。 通過(guò)四種鹽凍試驗(yàn)的對(duì)比，混凝土在3%濃度鹽溶液中凍融損壞最為嚴(yán)重。溶液濃度越高，混凝土的耐久性越好。以3%濃度為例，混凝土的抗凍性依次為：CMA＞CaCl2＞NaCl＞Na2SO4(“＞”表示“優(yōu)于”)。根據(jù)混凝土抗凍性的定量化分析，利用MATLAB數(shù)值分析軟件擬合出不同濃度NaCl鹽凍環(huán)境下混凝土最大抗凍融次數(shù)經(jīng)驗(yàn)公式。為研究混凝土的鹽凍提供一定的參考，對(duì)道路除冰鹽的使用具有指導(dǎo)意義。
[Abstract]:Today, with the development of infrastructure construction, concrete is widely used in highway, bridge, airport, wharf, construction engineering and so on, in order to ensure the normal operation of winter traffic. Snow melting agent (deicing salt) is widely used. At present, there are many kinds of deicing salt in the market. Different deicing salts have different damage degree to road concrete, different erosion mechanism and different pollution degree to ecological environment. Therefore, it is of great significance to study the frost durability of concrete under different deicing salt environment. In this paper, through the rapid freeze-thaw test method of ordinary concrete, we analyze the different salt solution NaCl-CaCl2CMA-Na _ 2SO _ 4) and the different concentration of NaCl-CaCl _ 2-CMA-Na _ 2SO _ 4). The influence on the frost resistance of concrete is obtained, and the variation law of mass loss, relative dynamic elastic modulus and cube compressive strength of concrete under salt freezing environment is obtained. With the increase of freeze-thaw times, the surface peeling degree of concrete specimens is gradually deepened and the relative dynamic modulus of elasticity is increased under the environment of NaCl salt freezing. The compressive strength of the cube decreased gradually. 3% NaCl salt frozen the most serious damage, freeze-thaw 100 times after the mass loss of 7.55, the relative dynamic modulus of elasticity is 13.34%. The compressive strength of concrete cube is decreased by 60. The concrete durability is similar to that of CaCl _ 2 salt frozen concrete under NaCl and CaCl2 salt freezing environment, and the corrosion of concrete by CaCl _ 2 salt freezing is relatively small. Secondly, at the same freezing and thawing times, the state of the concrete is arranged from good to bad in the order of: 25CMA > 12CMA > 6CMA > 3CMA; Once again, Na _ 2SO _ 4 is not soluble in water, salt freezing is only 50 times, the relative dynamic modulus of elasticity is lower than 60%. After 100 times of salt freezing, the coarse aggregate of concrete is exposed, and the mass loss increases rapidly. The relative dynamic elastic modulus is only 20. Through the comparison of four kinds of salt freezing tests, the damage of concrete in 3% concentration salt solution is the most serious. The higher the solution concentration, the better the durability of concrete. Take 3% concentration as an example. The frost resistance of concrete is in the order of: CMA > CaCl2 > NaCl > Na _ 2SO _ 4 (">" means "superior"). According to the quantitative analysis of the frost resistance of concrete. The empirical formula of maximum freeze-thaw resistance of concrete under different concentrations of NaCl salt freezing environment is fitted by using MATLAB numerical analysis software, which provides a certain reference for the study of concrete salt freezing. It is of guiding significance for the use of deicing salt in road.
【學(xué)位授予單位】：內(nèi)蒙古科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：U414

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