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一、前言 混凝土是一种力学强度高而且耐久性很好的材料,因此目前是用量最大的建筑材料,在可预见的将来,也将是用途最广、用量最大的结构材料。然而,自七十年代以来混凝土的耐久性越来越成为工程界特别关注的问题。在北美和欧洲发达国家出现了许多混凝土结构在没有达到预期的使用年限（比如说50～100年）即破坏甚至断裂的实例,以至许多混凝土结构需要提前修补,特别在恶劣的使用环境下的高速公路、桥梁、海港混凝土。据说美国混凝土结构的修理费用每年高达百亿美元。在我国,五十年代建国初期,在老科学家的带动下,对大
I. INTRODUCTION Concrete is a material with high mechanical strength and good durability. Therefore, it is currently the most used building material. In the foreseeable future, concrete will also be the most widely used and most used structural material. However, the durability of concrete since the 1970s has increasingly become an issue of particular concern to the engineering community. In developed countries in North America and Europe there have been many examples of concrete structures that have not reached the expected age (for example, 50 to 100 years), that is, destroyed or even broken, and that many concrete structures need to be repaired in advance, especially in harsh environments. Highways, bridges, harbor concrete. It is said that the repair cost of American concrete structures amounts to 10 billion U.S. dollars per year. In our country, in the early 1950s when the founding of the People’s Republic of China