一、前言 混凝土作为主要的结构材料正被用于各种新型结构上,如高速公路、桥梁、高层和超高层建筑、海港工程、地下工程等。因此对混凝土材料和工艺提出了很多新的要求和问题,其中特别是耐久性问题。 混凝土在特定使用环境下由于耐久性不好非力学强度不够而遭破坏的实例越来越多,如混凝土枕轨的碱-集料反应破坏,北方某高速公路建成后不到两年因撒除冰盐路面破坏,北方某给水结构物新建不久受冻破坏,海港区混凝土结构物和电杆因钢筋锈蚀的破坏等等。然而,混凝土耐久性问题迄今没有得到建设单位、设计院和工程单位的应有重视。这个问题如不及时解决,随着工程建设的扩大,国家将蒙受越来越大的经济损失。 目前混凝土耐久性存在问题的原因是多方面的,作为技术人员难以全面分析,我们体会可能有: (1)有关单位考虑近期效益多,长远利 I. INTRODUCTION As the main structural material, concrete is being used in various new structures, such as highways, bridges, high-rise and high-rise buildings, harbor projects, and underground projects. Therefore, a lot of new requirements and problems have been put forward for concrete materials and processes, among which durability issues are especially. There are more and more instances of concrete being damaged due to poor durability and insufficient non-mechanical strength in specific use environments. For example, the alkali-aggregate reaction of concrete sleepers is destroyed, and less than two years after the construction of a highway in the north, it was removed. Ice and salt pavement damage, a new water supply structure in the north will be frozen and destroyed soon, and the concrete structures and poles in the harbor area will be damaged due to corrosion of steel bars. However, the durability of concrete has not received due attention from construction units, design institutes and engineering units so far. If this problem is not solved in time, the country will suffer more and more economic losses as the construction of the project expands. At present, there are many reasons for the problems of concrete durability. As technical personnel are difficult to fully analyze, our experience may include: (1) Relevant units consider many benefits in the near term and long-term benefits.