防护涂层对东北沿海地区混凝土结构抗冻性能的影响
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摘要
选用聚脲、聚氨酯、环氧砂浆3种防护涂层对东北沿海区域混凝土做表面处理后进行快速冻融试验,结果表明与未涂覆防护涂层的混凝土相比,涂覆防护涂层的混凝土质量损失率降低,相对动弹性模量提高,防护涂层的抗冻性能由强到弱的顺序为:环氧砂浆涂层>聚氨酯涂层>聚脲涂层;防护涂层可隔离腐蚀环境与混凝土接触,延缓腐蚀性物质进入,减缓混凝土内部的无害孔向多害孔与有害孔转变的趋势,改善混凝土的抗冻性能,延长混凝土结构的使用寿命。
Located in the northeast coastal area, the concrete structure of Dalian is complex, which causes serious damage to the offshore concrete structure in the area. In this regard, this paper selects three kinds of protective coatings of polyurea, polyurethane and epoxy mortar to surface the concrete, and the indoor rapid freeze-thaw test was carried out to analyze the effect of the coating on the frost resistance of concrete. The mercury intrusion test was carried out on the concrete samples before and after the freezethaw cycle to analyze the pore structure changes before and after corrosion of the coated concrete. The test results show that compared with the uncoated protective concrete, the mass loss rate of the concrete coated with protective coating is reduced, the relative dynamic elastic modulus is increased, and the anti-freezing performance of the protective coating is from strong to weak: Oxygen mortar coating > polyurethane coating > polyurea coating. Because the protective coating isolates the corrosive environment from contact with the concrete, delays the entry of corrosive substances, slows the tendency of the harmless pores inside the concrete to transform into the harmful holes and harmful pores, improves the frost resistance of the concrete, and prolongs the use of the concrete structure life.
Located in the northeast coastal area, the concrete structure of Dalian is complex, which causes serious damage to the offshore concrete structure in the area. In this regard, this paper selects three kinds of protective coatings of polyurea, polyurethane and epoxy mortar to surface the concrete, and the indoor rapid freeze-thaw test was carried out to analyze the effect of the coating on the frost resistance of concrete. The mercury intrusion test was carried out on the concrete samples before and after the freezethaw cycle to analyze the pore structure changes before and after corrosion of the coated concrete. The test results show that compared with the uncoated protective concrete, the mass loss rate of the concrete coated with protective coating is reduced, the relative dynamic elastic modulus is increased, and the anti-freezing performance of the protective coating is from strong to weak: Oxygen mortar coating > polyurethane coating > polyurea coating. Because the protective coating isolates the corrosive environment from contact with the concrete, delays the entry of corrosive substances, slows the tendency of the harmless pores inside the concrete to transform into the harmful holes and harmful pores, improves the frost resistance of the concrete, and prolongs the use of the concrete structure life.
引文
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[2]张宝胜,干伟忠,陈涛.杭州湾跨海大桥混凝土结构耐久性解决方案[J].土木工程学报,2006(6):72-77.
[3]李中华,巴恒静.除冰盐环境下混凝土有机硅涂层防护性能研究[J].中国矿业大学学报,2009,38(1):41-45.
[4]刘荣桂,刘涛,周伟玲,等.受疲劳荷载作用后的预应力混凝土构件冻融循环试验与损伤模型[J].南京工业大学学报(自然科学版),2011,33(3):22-27.
[5]POWERS.A working hypothesis for further studies of frost resistance of concrete[J].Journal of American Concrete Institute,16(4):245-272.
[6]中国硅酸盐学会.吴中伟院士从事科教工作六十年学术讨论会论文集[C].中国硅酸盐学会,2004.