Title: Long-Term Performance of Concrete Incorporating Ground Granulated Blast Furnace Slag
Author(s): D. Boubitsas
Publication: Symposium Paper
Appears on pages(s): 265-280
Keywords: chloride migration; compressive strength; concrete; durability; granulated blast furnace slag; k-value
The aim of this paper is to introduce a method for determining the coefficient of efficiency, the k-value, with respect to chloride migration in concrete. Some results for ground granulated blast furnace slag are presented and compared with traditional k-values for compressive strength. Finally, some recommendations on how to use the k-values and how to improve standards and regulations are given. Standards normally give a single k-value for each type of addition, regardless of what environment the concrete will be exposed to. The results in the investigation, how-ever, clearly indicate that this is too great a simplification. For chloride migration, for example, the k-value is three times higher for slag than is the corresponding k-value for compressive strength. For a reliable service life prediction of concrete structures produced with concrete containing additions, it is, therefore, necessary to find relevant k-values for different types of degradation mechanisms. The most important mechanisms are corrosion induced by carbonation, by chlorides from the sea or by other chlorides, freeze/thaw attack with or without chlorides and perhaps also chemical attack.