本文選題：灌漿缺陷 + 鋼絞線銹蝕　； 參考：《哈爾濱工業(yè)大學(xué)》2015年碩士論文

【摘要】：后張預(yù)應(yīng)力橋梁由于經(jīng)濟(jì)及結(jié)構(gòu)優(yōu)勢(shì),是預(yù)應(yīng)力橋梁廣泛使用的結(jié)構(gòu)類型。實(shí)際工程中,后張預(yù)應(yīng)力橋梁常出現(xiàn)孔道灌漿不密實(shí)情況,當(dāng)處于沿海及冬季需除冰鹽融雪地區(qū)時(shí),其長(zhǎng)期受到氯離子侵蝕作用,預(yù)應(yīng)力筋易腐蝕,造成結(jié)構(gòu)使用壽命縮短�；谏鲜霰尘�,本文以后張預(yù)應(yīng)力橋梁常見(jiàn)孔道灌漿缺陷(完全無(wú)灌漿、平行灌漿、垂直灌漿)為基礎(chǔ),研究了氯鹽環(huán)境孔道灌漿缺陷下鋼絞線銹蝕狀況。完全無(wú)灌漿類型中鋼絞線暴露在氯離子侵蝕溶液中,通過(guò)測(cè)試其極化電阻、極化曲線、質(zhì)量損失等參數(shù),研究氯離子濃度對(duì)鋼絞線銹蝕影響。研究表明,氯離子濃度增加時(shí),鋼絞線銹蝕速度增加。平行及垂直灌漿類型中鋼絞線部分暴露在氯離子侵蝕溶液中,部分處于水泥漿保護(hù)中,通過(guò)測(cè)試氯離子侵蝕溶液中鋼絞線與水泥漿中鋼絞線未通過(guò)導(dǎo)線連接時(shí)各自銹蝕電位、交流阻抗譜及連接后各自耦合電位、耦合交流阻抗譜、銹蝕形貌、質(zhì)量損失及二者之間電偶電流,研究此兩種孔道灌漿缺陷下鋼絞線銹蝕機(jī)理與氯離子濃度、陰陽(yáng)極面積比對(duì)銹蝕速度影響。研究表明,平行及垂直灌漿體系氯離子侵蝕溶液及水泥漿中鋼絞線連接后,前者電勢(shì)升高,后者電勢(shì)降低,二者形成宏電池作用,前者作為宏電池陽(yáng)極,后者作為宏電池陰極;形成宏電池后,陽(yáng)極與陰極低頻段容抗弧半徑均減小,陽(yáng)極銹蝕速度增加。平行灌漿體系中侵蝕溶液氯離子濃度及陰陽(yáng)極面積比增加時(shí),陽(yáng)極銹蝕速度增加;氯離子濃度0.1%、平行及垂直灌漿體系陰陽(yáng)極面積比60:1時(shí),鋼絞線銹蝕速度最快的灌漿類型是平行灌漿類型,其次是垂直灌漿類型,最后是完全無(wú)灌漿類型。采用混合電勢(shì)理論及數(shù)值方法預(yù)測(cè)了孔道平行及垂直灌漿類型中宏電池陽(yáng)極銹蝕速度,結(jié)果表明,混合電勢(shì)理論的預(yù)測(cè)結(jié)果與實(shí)驗(yàn)值有較大偏差,數(shù)值方法預(yù)測(cè)結(jié)果與試驗(yàn)值相近。在此基礎(chǔ)上,通過(guò)數(shù)值方法建立工程實(shí)際模型,研究了孔道空隙變化對(duì)鋼絞線銹蝕速度影響,研究表明,預(yù)應(yīng)力孔道出現(xiàn)平行空洞時(shí),孔道空隙越小,陽(yáng)極銹蝕速度越快;出現(xiàn)垂直空洞時(shí),銹蝕速度最快的點(diǎn)是陰陽(yáng)極交點(diǎn)。
[Abstract]:Post-tensioned prestressed bridges are widely used in prestressed bridges because of their economic and structural advantages. In practical engineering, post-tensioned prestressed bridges often occur the condition that the grouting of holes is not dense. When it is in the coastal and winter areas where deicing and salt melting snow, it is subjected to chloride ion erosion for a long time, and the prestress tendons are easy to corrode, thus shortening the service life of the structure. Based on the above background, this paper studies the corrosion of steel strands in chloride environment on the basis of common grouting defects (no grouting, parallel grouting, vertical grouting) of post-tensioning bridges. The steel strand without grouting type was exposed to chloride ion erosion solution. The influence of chloride ion concentration on the corrosion of steel strand was studied by measuring the parameters such as polarization resistance polarization curve and mass loss. The results show that the corrosion rate of steel strand increases with the increase of chloride ion concentration. The steel strands in parallel and vertical grouting types are partially exposed to chloride ion erosion solution and partly in cement slurry protection. The corrosion potential of the steel strand in the chloride ion erosion solution and the steel strand in the cement slurry is tested when the wire is not connected through the wire, Ac impedance spectrum and coupling potential, coupled AC impedance spectrum, corrosion morphology, mass loss and electric coupling current between them are studied. The corrosion mechanism and chloride concentration of steel strand under these two defects are studied. The effect of area ratio of anode and cathode on corrosion rate. The results show that the potential of the former increases and the potential of the latter decreases after the connection of the chloride ion erosion solution and the steel strand in the cement slurry in parallel and vertical grouting systems. The former acts as the anode of the macro cell and the latter as the cathode of the macro cell; the former is used as the anode of the macro cell and the latter is used as the cathode of the macro cell. After the formation of macro cell, the radius of capacitive arc resistance of anode and cathode in low frequency range decreased, and the corrosion rate of anode increased. In parallel grouting system, the corrosion rate of anode increases with the increase of chloride concentration and the area ratio of anode to anode in the erosion solution, and the anode corrosion rate increases when the concentration of chlorine ion is 0.1, and the area ratio of anode and anode in parallel and vertical grouting system is 60:1, The fastest grouting type of steel strand corrosion is parallel grouting type, followed by vertical grouting type, and no grouting type. The corrosion rate of the anode of macro cell in parallel and vertical grouting type is predicted by using mixed potential theory and numerical method. The results show that the prediction result of mixed potential theory is quite different from the experimental value. The predicted results by the numerical method are close to the experimental values. On this basis, the actual engineering model is established by numerical method, and the influence of pore void variation on the corrosion velocity of steel strand is studied. The results show that the smaller the pore gap is, the faster the anode corrosion rate is when the parallel cavity appears in the prestressing channel. When a vertical cavity appears, the fastest point of corrosion is the intersection of the cathode and the cathode.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：U445.57

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相關(guān)期刊論文 前1條

1 黃玉娟;侯書(shū)恩;靳洪允;趙新穎;許亮;;預(yù)應(yīng)力孔道灌漿材料性能的影響因素[J];混凝土與水泥制品;2009年06期

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本文編號(hào)：1793500