Title: Effect of Silica Fume Addition on the Durability of Alkali-Resistant Glass Fibrer in Cement Matrices
Author(s): V. T. Yilmaz and F. P. GlasserI
Publication: Symposium Paper
Appears on pages(s): 1151-1166
Keywords: alkali-aggregate reactions; degradation; durability; flexural strength; glass fibers; reinforced concrete; silica fume; Materials Research
The durability of alkali-resistant glass fiber in cement matrixes with and without silica fume was investigated. Several attack modes such as hydroxylation, mass dissolution, and notching by calcium hydroxide crystals were distinguished. The effect of silica fume addition was found to be slight; it greatly reduced the calcium hydroxide content of the cement matrix and inhibited notching attack, but it did not reduce the internal pH sufficiently to inhibit hydroxylation and mass dissolution. The flexural strength of cement pastes at 20 C with and without silica fume initially increased during the first month and thereafter started to decrease and eventually leveled off at longer ages. The addition of silica fume gave only a marginal improvement to the elastic properties of composites at 20 C. At 55 C, the flexural strengths of both formulations were observed to decrease very rapidly, approaching the flexural strength of the unreinforced matrix.