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受海水中氯离子侵蚀,沿海混凝土桥梁在水位变动区、浪溅区的构件使用不久即出现严重钢筋锈蚀、混凝土剥落,导致结构耐久性的降低、甚至失效,影响桥梁安全。通过总结国内外受氯离子侵蚀的钢筋混凝土桥梁腐蚀研究,指出了腐蚀的普遍性和严重性,及设计时未考虑这一问题带来的高额维修费用。现有的混凝土耐久性防护方法是通过改变钢筋周围的环境,延长钢筋开始锈蚀时间或减缓钢筋锈蚀速度,但碳钢的本性决定了现有防护措施无法从根本上解决这一难题。相距约200m在沿海建设的不锈钢筋混凝土桥梁与普通钢筋混凝土桥梁,不锈钢筋混凝土桥梁使用近70年未锈蚀,而普通钢筋混凝土桥梁使用20多年即因钢筋锈蚀而拆除,证明不锈钢筋混凝土在海洋环境具有优异的耐久性。20世纪80年代,不锈钢筋研究逐渐增多,90年代开始在高腐蚀环境的结构中得到了应用,收到了很好的效果,且美英等国已经将不锈钢筋列入钢筋混凝土用钢筋范围。
Affected by chloride ion in seawater, coastal concrete bridges are in fluctuating water level. Serious steel corrosion and concrete spalling shortly after the use of components in the splash zone cause the durability of the structure to decrease or even fail, affecting the safety of the bridge. By summarizing the corrosion of reinforced concrete bridges corroded by chloride ions both at home and abroad, the universality and seriousness of corrosion are pointed out, and the high maintenance costs caused by this problem are not considered in the design. The existing concrete durability protection method is by changing the environment around the rebar to extend the bar to start the corrosion time or reduce the corrosion rate of steel, but the nature of carbon steel determines the existing protective measures can not fundamentally solve this problem. The stainless steel reinforced concrete bridges and ordinary reinforced concrete bridges with a distance of about 200m are used in the coastal area. The stainless steel reinforced concrete bridges have been used for nearly 70 years without rusting. However, ordinary reinforced concrete bridges have been used for more than 20 years and are removed due to steel corrosion. Has excellent durability. In the 1980s, the research of stainless steel reinforcement gradually increased. Since the 1990s, it has been applied in the structure of highly corrosive environment and received good results. And the United States and Britain have listed stainless steel bars in the range of steel bars for reinforced concrete.