Durability of Concrete

尽管混凝土技术取得了发展，但极端环境下的混凝土继续过早退化。这在一定程度上是由于使用新材料时没有充分考虑副作用，但主要是因为使用了不充分的试验、规范或施工方法，以及对影响耐久性的所有因素缺乏了解。水泥浆体基质和浆体-骨料界面区域的孔结构和由此产生的抗流体渗透能力决定了混凝土对大多数破坏原因的耐久性。在本提案中，将继续研究这些特性在耐氯离子渗透、钢筋腐蚀、冻结和融化、碱-集料反应和抗硫酸盐方面的应用。还在研究耐久性的其他方面，如抗裂性(抗热和与水分有关的收缩)和改进的基于耐久性的性能规格。

In spite of developments in concrete technology, concrete in extreme environments continues to prematurely deteriorate. In part, this results from the use of new materials without adequate consideration of side effects, but mostly from the use of inadequate tests, specifications or construction methods, and also from a lack of understanding of all the factors which influence durability. The pore structure and resultant fluid penetration resistance of the cement paste matrix and paste-aggregate interfacial regions govern the durability of concrete to most causes of distress. In this proposal, these properties will continue to be studied with applications in resistance to: chloride ingress, reinforcement corrosion, freezing and thawing, alkali-aggregate reactions, and sulphate resistance. Other aspects of durability such as crack resistance (to thermal and moisture-related shrinkage) and improved durability-based performance specifications are also being studied.