Manager of Materials Division, Klohn Leonoff Ltd., Consulting Engineers, Calgary, Alberta
The durability of concrete is obviously a complex topic. This paper deals with an overview in four parts: The first part consists of durability as affected by more than 200 individual separate items involved in its constituent materials; the effect of practical matters in preparing and handling concrete aggregates; cement storage and handling and construction techniques; the physical properties of the hardened concrete; nature of exposure of the concrete; and finally the types of loading to which concrete is exposed. Second, examples of durability of nonstructural exposed concrete are given in terms of resistance to freeze-thaw forces in relation to air-void characteristics of normal concrete. Third, an example of nondurable, load bearing structural concrete is illustrated along with the causes of distress and method of repair. Finally, a recent example of a high strength structural concrete bridge deck containing a superplasticizer is presented in terms of its durability characteristics. Detailed data on each of these four classifications has been referenced to facilitate a more in-depth study by those parties who may have an interest in one or more of those topics.