不同措施对热带海洋砼结构服役寿命的影响

海工钢筋混凝土结构由于长期受到海洋盐雾大气、浪溅与潮汐、高温等环境因素作用,大量氯离子侵入混凝土中,致使结构中的钢筋严重锈蚀,从而使混凝土结构难以达到50年的设计寿命要求.本文基于修正的氯离子扩散理论与可靠度理论,通过南海实际工程来探讨一些结构措施和附加措施对海工混凝土服役寿命的影响.结果表明:增大结构的保护层厚度能有效延长结构的服役寿命.对混凝土结构施加一定的附加防护措施,也能够有效地延长混凝土结构在热带海洋环境下的服役时间.最有效的附加防护措施是采用不锈钢钢筋,但是价格太高而应用受限,比较适用的是硅烷外涂或者使用阻锈剂,但对于一维结构而言仅仅使用其中一种并不能保证结构50年的设计寿命.

Effects of Various Measures on Service Life of Concrete Structure in Tropical Marine Environment

Due to the long-term corrosion affected by environmental factors, such as sea salt spray, wave-splashing and tidal, a lot of chloride ions in concrete lead to a serious corrosion in marine reinforced concrete structure.As a result, the marine concrete structure is difficult to meet the requirement of 50 years for design service life. In the present work, based on the chloride ion diffusion theory and reliability theory, the effects of structural measures and additional measures on the service life of practical structure in the South China Sea were discussed. The results indicate that the thicker concrete cover thickness can effectively extend the service life of concrete structure. Besides, additional measures also can extend the service life of the structure in tropical marine environment, the most effective method is to use stainless steel instead of ordinary reinforced steel, and however, the high price of stainless steel will limit its application. Compared with other kinds of additional measures,coated with silicone or adding corrosion inhibitor is an effective measure to marine concrete structure. But only one additional measure was used in one dimensional concrete structure that cannot meet the requirement of 50 years of designed service life.