Effectiveness of Granulated Blast Furnace Slag in Preventing Alkali-Silica Reaction
D. D. Higgins and M. D. Connel
Appears on pages(s):
accelerated tests; alkali-aggregate reactions; blast furnace slag; expansion; slags; specifications; Materials Research
In a program covering a wide range of mixtures, three portland cements and two ground granulated blast furnace slags (GGBS) were used to investigate the relationship between alkali content and ASR expansion. Length changes were monitored, for several years, on concrete prisms made with a reactive natural aggregate. The prisms were moist cured at 20 C and 38 C. Storage at 38 C was found to be an accelerated test which correlated will with storage at 20 C. At 20 C, the rate of expansion was some four times slower than at 38 C. Nonetheless, there was very good consistency between the two temperatures in classifying mixtures either expanding or nonexpanding. Current indications are that the magnitudes of ultimate expansions are independent of temperature. The mixtures containing GGBS tolerated much greater alkali contents in the concrete without expansion. This effect was more pronounced for higher proportions of GGBS. The results of the program are discussed in this paper in relation to various rules which have been proposed to take advantage of the effectiveness of GGBS in preventing ASR.