钢筋混凝土的防水处理

Water repellent treatment as applied to protect reinforced conerete structures

介绍了混凝土防水处理技术的发展状况。论述了防水处理对侵蚀环境中的钢筋、预应力钢筋混凝土结构的保护作用,以及防水处理在混凝土表面形成氯离子隔离层的情况。防水剂的渗透深度和硅烷含量是防水处理的两个重要参数,渗透深度与接触时间有关,延长混凝土与防水剂的接触时间或采用新型的乳液、凝胶等防水剂,都能使渗透深度达到10mm以上,防水处理后的混凝土吸水系数不到原来的十分之一。为了检测混凝土防水处理效果,将处理与未处理的混凝土浸入海水之中28天,之后测量混凝土中氯离子含量分布,防水处理建立的氯离子隔离层具有优越的抵抗氯离子渗透性。

First a general overview on the potential of water repellent treatment of concrete and concrete structure is given.Special emphasis is placed on the protection of reinforced and prestressed concrete structures exposed to marine environment or in contact with water containing chloride ions from de-icing salt.It has been investigated if an effcient chloride barrier can be established by means of water repellent treatment.The importance of a sufficient penetration depth as well as a sufficient amount of watet repellent agent for the efficiency of the surface treatment is underlined.Allowing long enough contact times between the agent and the concrete surface or using advanced types of water repellent systems such as cream and gel make it possible to reach a penetration depth of 10mm and more.The water absorption coefficient measured on treated concrete is lower than one tenth related to value of the untreated material.Treated and untreated concrete are exposed to saline water for 28 days to examine the effect of water repellent treatment.Then the chloride profiles are determined.The chloride barrier built up by water repellent treatment has very good performance.