本文關(guān)鍵詞： 硫酸鹽 鎂鹽 混凝土 微觀形貌　出處：《農(nóng)業(yè)工程學(xué)報》2015年09期 　論文類型：期刊論文

【摘要】：混凝土結(jié)構(gòu)通常受土壤環(huán)境水中硫酸鹽和鎂鹽溶液的侵蝕。為了探究硫酸鹽和鎂鹽復(fù)合溶液侵蝕后純水泥混凝土和摻礦粉微粉高性能混凝土的抗侵蝕性能,該研究設(shè)計了3個水膠比和2個礦粉摻量,經(jīng)加水拌合、成型試件1050個,養(yǎng)護28 d后將其分別浸泡于硫酸鹽和鎂鹽溶液中,侵蝕至規(guī)定齡期后測試其抗蝕系數(shù)、微觀形貌。結(jié)果表明:水膠比為0.50時,混凝土界面中的孔隙多、孔徑大,最大孔徑為372.5μm,即使水膠比降低到0.35時,其孔結(jié)構(gòu)的改善也不明顯。當(dāng)純水泥混凝土試件在SO42-2 500 mg/L和Mg2+1 400 mg/L的硫酸鹽鎂鹽中侵蝕4個月后,其孔隙中充滿了Ca SO4·2H2O、3Ca O·Al2O3·3Ca SO4·32H2O(AFt)、Mg(OH)2和Mg O·Si O2·H2O等侵蝕產(chǎn)物,致使混凝土內(nèi)部產(chǎn)生裂縫,邊角處開始出現(xiàn)剝落,甚至變得酥松,表面漿體脫落嚴(yán)重,粗細集料分離等現(xiàn)象。當(dāng)侵蝕時間超過2月時,其侵蝕系數(shù)隨侵蝕齡期的延長呈降低的趨勢,且均在0.85以下,說明32.5級普通硅酸鹽水泥抗硫酸鹽鎂鹽侵蝕的能力是有限的。礦渣微粉摻入后,混凝土界面的孔隙不僅極少,而且孔徑也較小,最大孔徑分別約為水膠比為0.50時的1/7和1/8,同時也減少了易被侵蝕的水化產(chǎn)物Ca(OH)2的含量,使混凝土界面結(jié)構(gòu)密實程度增加,水膠比越低越明顯。在高濃度的硫酸鹽和鎂鹽(SO42-20 250 mg/L和Mg2+2 800 mg/L)的雙重強侵蝕12個月后,試件邊緣仍未發(fā)現(xiàn)侵蝕產(chǎn)物以及Mg SO4·7H2O、Na2SO4·10H2O和Mg2(OH)3Cl·4H2O等晶體,其抗蝕系數(shù)仍在0.85以上,未有降低的趨勢,表明礦渣微粉的摻入能顯著改善32.5級普通硅酸鹽水泥所配制高性能混凝土的抗侵蝕性能。該研究可為混凝土在農(nóng)業(yè)灌溉工程(壩基礎(chǔ)、閘基礎(chǔ)和渠道等)和大棚混凝土基礎(chǔ)工程的使用提供數(shù)據(jù)支撐與理論基礎(chǔ)。
[Abstract]:The concrete structure is usually eroded by sulfate and magnesium solution in soil environment water. In order to investigate the corrosion resistance of pure cement concrete and high performance concrete mixed with mineral powder after erosion by sulfate and magnesium salt composite solution. In this study, three water-binder ratios and two mineral powder contents were designed, and 1050 samples were formed by mixing with water. After 28 days of curing, the samples were immersed in sulfate and magnesium solution respectively. The corrosion resistance coefficient and microstructure of the concrete were measured after erosion to the specified age. The results showed that when the water-binder ratio was 0.50, the pore size in the interface of concrete was large and the maximum pore size was 372.5 渭 m. Even when the water-binder ratio is reduced to 0.35. The improvement of pore structure was not obvious. When pure cement concrete specimens were corroded in SO42-2 500 mg/L and Mg2 1 400 mg/L magnesium sulfate for 4 months. The pore is filled with Ca SO4 路2H 2O 3CA O 路Al2O3 路3Ca SO4 路32H 2O. Corrosion products such as Mg(OH)2 and MgO 路Sio _ 2 路H _ 2O lead to cracks in the concrete, the flaking of the edges and even the looseness of the surface slurry. When the erosion time exceeds February, the erosion coefficient decreases with the extension of erosion age, and the erosion coefficient is below 0. 85. The results show that the ability of 32.5 grade Portland cement to resist magnesium sulfate erosion is limited, and the pore size of concrete interface is not only small but also small after the addition of slag powder. The maximum pore size is about 1/7 and 1 / 8 when the water-binder ratio is 0.50, which also reduces the content of Ca(OH)2, which is easy to be corroded, and increases the compactness of concrete interface structure. The lower the water-binder ratio is, the more obvious it is, after 12 months of double strong erosion with high concentrations of sulfate and magnesium salt so _ 42-20 250 mg/L and Mg2 2 800 mg 路L ~ (-1). No erosion products and crystals such as mg SO4 路7H _ 2O Na _ 2SO _ 4 路10H _ 2O and Mg2(OH)3Cl 路4H _ 2O were found at the edge of the specimen. The corrosion resistance coefficient is still above 0.85, and there is no decreasing trend. The results show that the addition of slag powder can significantly improve the corrosion resistance of high performance concrete prepared by 32.5 grade ordinary Portland cement. This study can be used in the agricultural irrigation project (dam foundation). The use of concrete foundation and shed provides data support and theoretical basis.
【作者單位】： 新疆農(nóng)業(yè)大學(xué)水利與土木工程學(xué)院;新疆農(nóng)業(yè)大學(xué)草業(yè)與環(huán)境科學(xué)學(xué)院;
【基金】：國家自然科學(xué)基金資助(50969010) 國家高等學(xué)校博士點專項科研基金資助(20106504110005) 新疆水利水電工程重點學(xué)科基金資助(XJzdxk-2010-02-12) 新疆維吾爾自治區(qū)研究生科研創(chuàng)新項目資助(XJGRI2014072)
【分類號】：TU528
【正文快照】： 吳福飛,侍克斌,董雙快,等.硫酸鹽鎂鹽復(fù)合侵蝕后混凝土的微觀形貌特征[J].農(nóng)業(yè)工程學(xué)報,2015,31(9):140-146.Wu Fufei,Shi Kebin,Dong Shuangkuai,et al.Microstructure characteristics of concrete after erosion of magnesium salts andsulfates[J].Transactions of the Ch

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