多因素耦合作用下混凝土硫酸鹽腐蝕性能研究
發(fā)布時間：2018-11-13 19:31
【摘要】：實際服役的混凝土結(jié)構(gòu)暴露于復(fù)雜的硫酸鹽環(huán)境中，其劣化破壞是由材料、物理、化學(xué)、應(yīng)力等諸多因素共同作用、相互耦合導(dǎo)致的。在地下混凝土結(jié)構(gòu)中，全部埋于或浸泡于地下硫酸鹽環(huán)境中的混凝土構(gòu)件會受到硫酸鹽全浸泡腐蝕，而半埋或半浸泡于地下硫酸鹽環(huán)境中的混凝土構(gòu)件則會受到干濕循環(huán)腐蝕。同時，一面與腐蝕環(huán)境接觸、而另一面暴露于空氣中的混凝土構(gòu)件受到的硫酸鹽腐蝕稱為單面腐蝕。 本文對全浸泡腐蝕、干濕循環(huán)腐蝕和單面腐蝕分別進(jìn)行試驗研究，選取影響硫酸鹽腐蝕的因素及其水平，即Na2SO4溶液濃度（2%、5%和10%）、水膠比（0.4、0.5和0.6）和粉煤灰摻量（0%、10%和20%），分析多因素耦合作用下混凝土硫酸鹽腐蝕性能的退化規(guī)律，并對腐蝕過程進(jìn)行理論解釋。 在全浸泡腐蝕試驗中，抗壓強(qiáng)度和對測聲速隨腐蝕時間的增加而表現(xiàn)出先增大后減小的趨勢；對于強(qiáng)度損失率和腐蝕損傷度，腐蝕前期為負(fù)值且絕對值先變大后變小，腐蝕后期為正值且不斷增大。引入腐蝕過渡層，硫酸鹽腐蝕混凝土的過程就是腐蝕過渡層進(jìn)一步劣化為腐蝕損傷層并不斷向從外向里推進(jìn)的。計算出腐蝕損傷層厚度，分析腐蝕損傷層混凝土的聲速及其與未腐蝕層聲速的比值隨腐蝕時間的變化規(guī)律。正交試驗分析表明：最強(qiáng)腐蝕組合是A3B3C1，最弱腐蝕組合是A1B1C2；Na2SO4溶液濃度影響最大，水膠比次之，粉煤灰摻量影響最小；并建立腐蝕損傷層厚度與腐蝕時間及因素的計算模型。 在干濕循環(huán)腐蝕試驗中，腐蝕損傷度和腐蝕損傷層厚度均為正值且隨腐蝕時間增加而不斷增大，每一次循環(huán)都經(jīng)歷了“腐蝕→填充→損傷→損傷累積→劣化、開裂”的腐蝕過程。與全浸泡腐蝕相比，干濕循環(huán)腐蝕更厲害，，且以硫酸鹽物理結(jié)晶腐蝕為主，水分的傳輸在干濕循環(huán)硫酸鹽腐蝕過程中起到了關(guān)鍵作用。Na2SO4溶液濃度對干濕循環(huán)條件下的混凝土硫酸鹽腐蝕的影響顯著。 在單面腐蝕試驗中，吸附區(qū)混凝土表現(xiàn)出腐蝕破壞形態(tài)不同的三個區(qū)域——水膜區(qū)、結(jié)晶剝落區(qū)和吸附結(jié)晶區(qū)；吸附區(qū)混凝土的腐蝕損傷層厚度大于浸泡區(qū)混凝土，吸附區(qū)粉煤灰混凝土腐蝕也較嚴(yán)重。浸泡區(qū)中的水和SO42-離子在濕度梯度和濃度梯度的作用下沿壁厚或底厚方向由外向里擴(kuò)散；而吸附區(qū)中的水和SO42-離子在毛細(xì)壓力作用下沿壁高度方向由下向上遷移，并在蒸發(fā)作用下水分散失，SO42-離子向表層聚集。
[Abstract]:Concrete structures in service are exposed to complex sulphate environment and their deterioration and failure are caused by the interaction and coupling of materials, physics, chemistry, stress and so on. In the underground concrete structure, all the concrete members buried in or immersed in the underground sulfate environment will be completely corroded by sulfate, while the half-buried or semi-immersed concrete members in the underground sulfate environment will be corroded by dry-wet cycle. At the same time, the sulphate corrosion of concrete members exposed to air on one side is called one-sided corrosion. In this paper, the total immersion corrosion, dry and wet cycle corrosion and single side corrosion were studied respectively. The factors affecting sulfate corrosion and their levels were selected, that is, the concentration of Na2SO4 solution (2% and 10%). Water / binder ratio (0.4g / 0.5 and 0.6) and fly ash content (010% and 20%) were used to analyze the degradation law of sulfate corrosion performance of concrete under multi-factor coupling, and the corrosion process was explained theoretically. In the whole immersion corrosion test, the compressive strength and the sound velocity showed a tendency of first increasing and then decreasing with the increase of corrosion time. For the strength loss rate and corrosion damage degree, the initial value of corrosion is negative and the absolute value first increases and then becomes smaller, and the latter stage of corrosion is positive and increasing. With the introduction of corrosion transition layer, the process of sulphate corrosion of concrete is the process of further deterioration of the transition layer into corrosion damage layer and continuously advancing from outward to outward. The thickness of corrosion damage layer is calculated and the variation law of sound velocity and the ratio of sound velocity to that of non-corrosive layer with corrosion time are analyzed. The results of orthogonal test show that the strongest corrosion combination is A3B3C1and the weakest corrosion combination is A1B1C2Na2SO4 solution concentration, the ratio of water to binder is the second, and the content of fly ash is the least, and the calculation model of corrosion damage layer thickness, corrosion time and factors is established. In the dry and wet cycle corrosion test, the corrosion damage degree and the thickness of corrosion damage layer are both positive and increase with the increase of corrosion time. Cracking "corrosion process." Compared with total immersion corrosion, dry and wet cycle corrosion is more severe, and sulfate physical crystallization corrosion is the main corrosion. The moisture transport plays a key role in the process of wet and dry cycle sulfate corrosion. The concentration of Na2SO4 solution has a significant effect on the sulphate corrosion of concrete under dry and wet cycle conditions. In the single side corrosion test, the concrete in the adsorption zone shows three regions with different corrosion failure patterns: the water film region, the crystalline spalling zone and the adsorption crystallization zone. The thickness of corrosion damage layer of concrete in adsorption zone is larger than that of concrete in soaking area, and the corrosion of fly ash concrete in adsorption zone is more serious. The water and SO42- ions in the soaking zone diffused along the direction of wall thickness or bottom thickness under the action of humidity gradient and concentration gradient. However, the water and SO42- ions in the adsorbed region migrate along the direction of the wall height under capillary pressure, and the water is lost under evaporation, and the SO42- ion accumulates to the surface layer.
【學(xué)位授予單位】：中國礦業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TU528
本文編號：2330218
[Abstract]:Concrete structures in service are exposed to complex sulphate environment and their deterioration and failure are caused by the interaction and coupling of materials, physics, chemistry, stress and so on. In the underground concrete structure, all the concrete members buried in or immersed in the underground sulfate environment will be completely corroded by sulfate, while the half-buried or semi-immersed concrete members in the underground sulfate environment will be corroded by dry-wet cycle. At the same time, the sulphate corrosion of concrete members exposed to air on one side is called one-sided corrosion. In this paper, the total immersion corrosion, dry and wet cycle corrosion and single side corrosion were studied respectively. The factors affecting sulfate corrosion and their levels were selected, that is, the concentration of Na2SO4 solution (2% and 10%). Water / binder ratio (0.4g / 0.5 and 0.6) and fly ash content (010% and 20%) were used to analyze the degradation law of sulfate corrosion performance of concrete under multi-factor coupling, and the corrosion process was explained theoretically. In the whole immersion corrosion test, the compressive strength and the sound velocity showed a tendency of first increasing and then decreasing with the increase of corrosion time. For the strength loss rate and corrosion damage degree, the initial value of corrosion is negative and the absolute value first increases and then becomes smaller, and the latter stage of corrosion is positive and increasing. With the introduction of corrosion transition layer, the process of sulphate corrosion of concrete is the process of further deterioration of the transition layer into corrosion damage layer and continuously advancing from outward to outward. The thickness of corrosion damage layer is calculated and the variation law of sound velocity and the ratio of sound velocity to that of non-corrosive layer with corrosion time are analyzed. The results of orthogonal test show that the strongest corrosion combination is A3B3C1and the weakest corrosion combination is A1B1C2Na2SO4 solution concentration, the ratio of water to binder is the second, and the content of fly ash is the least, and the calculation model of corrosion damage layer thickness, corrosion time and factors is established. In the dry and wet cycle corrosion test, the corrosion damage degree and the thickness of corrosion damage layer are both positive and increase with the increase of corrosion time. Cracking "corrosion process." Compared with total immersion corrosion, dry and wet cycle corrosion is more severe, and sulfate physical crystallization corrosion is the main corrosion. The moisture transport plays a key role in the process of wet and dry cycle sulfate corrosion. The concentration of Na2SO4 solution has a significant effect on the sulphate corrosion of concrete under dry and wet cycle conditions. In the single side corrosion test, the concrete in the adsorption zone shows three regions with different corrosion failure patterns: the water film region, the crystalline spalling zone and the adsorption crystallization zone. The thickness of corrosion damage layer of concrete in adsorption zone is larger than that of concrete in soaking area, and the corrosion of fly ash concrete in adsorption zone is more serious. The water and SO42- ions in the soaking zone diffused along the direction of wall thickness or bottom thickness under the action of humidity gradient and concentration gradient. However, the water and SO42- ions in the adsorbed region migrate along the direction of the wall height under capillary pressure, and the water is lost under evaporation, and the SO42- ion accumulates to the surface layer.
【學(xué)位授予單位】：中國礦業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TU528
【參考文獻(xiàn)】
相關(guān)期刊論文 前10條
1 馬保國;羅忠濤;高小建;王信剛;王凱;;礦物摻合料對水泥砂漿硫酸鹽侵蝕的影響及機(jī)理[J];鐵道科學(xué)與工程學(xué)報;2006年06期
2 喬宏霞;何忠茂;劉翠蘭;;粉煤灰混凝土在硫酸鹽環(huán)境中的動彈性模量研究[J];粉煤灰綜合利用;2006年01期
3 申春妮,楊德斌,方祥位,張濤;混凝土硫酸鹽侵蝕影響因素的探討[J];水利與建筑工程學(xué)報;2004年02期
4 梁詠寧;黃君一;林旭健;季韜;;氯鹽對受硫酸鹽腐蝕混凝土性能的影響[J];福州大學(xué)學(xué)報(自然科學(xué)版);2011年06期
5 趙順波;楊曉明;;受侵蝕混凝土內(nèi)硫酸根離子擴(kuò)散及分布規(guī)律試驗研究[J];中國港灣建設(shè);2009年03期
6 何忠茂,杜雷,魏志勇;超聲波法檢測混凝土腐蝕厚度的研究[J];甘肅科技;1998年04期
7 左曉寶;孫偉;;硫酸鹽侵蝕下的混凝土損傷破壞全過程[J];硅酸鹽學(xué)報;2009年07期
8 金雁南;周雙喜;;混凝土硫酸鹽侵蝕的類型及作用機(jī)理[J];華東交通大學(xué)學(xué)報;2006年05期
9 李志國;試論鹽及溶液對混凝土及鋼筋混凝土的破壞[J];混凝土;1995年02期
10 覃維祖;高強(qiáng)與高性能混凝土工作度評價[J];混凝土;1997年03期
相關(guān)博士學(xué)位論文 前1條
1 杜朝偉;海底隧道襯砌水壓力及結(jié)構(gòu)受力特征研究[D];北京交通大學(xué);2011年
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