Influence of silica fume on alkali-silica reaction : A comprehensive study using accelerated tests on cement mortar bars

摘要

The major effect of added alkali content ( 0, 1, 1.25 wt.% of NaOH) in plain cement mortar bars cured in water for 1, 7 and 14 days and followed by exposure to 1 M NaOH at 80℃ for 14 days, showed significant degradation. Cement mortar bars prepared with 2 and 6 wt. % of silica fume as mineral admixture was based on the need of establishing critical limit for silica fume addition for alkali-silica reaction. Apart from length measurements, degradation of mortar bars was measured using ultrasonic pulse velocity, flexure strength and scanning electron microscopic techniques, before and after the accelerated tests. Critical quantity of silica fume beyond which its ineffectiveness on alkali-silica reaction was established.