BLENDED CEMENT IS A BAD RECOMMENDATION FOR MAGNESIUM SULFATE ATTACK
The service life of concrete structures depends on the environmental conditions and on thequality of concrete. Durability of concrete to sulfate attack is one of the environmentalproblems. Now, the most famous method to enhance the sulfate resistance of concrete is theuse of additions such as natural pozzolans, fly ashes or silica fume. A lot of researches coverthe effect of mineral admixtures on sodium sulfate resistance. From all these studies, the finalconclusion was the use of silica fume as cement replacement enhances the performance ofcement pastes and mortars to sodium sulfate attack. The performance of mineral admixtureson resisting the magnesium sulfate attack gives confusion data because of some researchersconcluded that the silica fume has a negative effect on enhancing the concrete resistance tomagnesium sulfate attack and others concluded the opposite. In this research work, an overalllong term study to evaluate the performance of mortars with mineral admixtures as cementreplacement to resist magnesium sulfate attack. Silica fume and metakaolin were used asmineral admixtures. The used percentages of cement replacement were 0, 10, 15, and 25％.Type Ⅰ and Type Ⅴ Portland cement were used with 0.5 and 0.4 w/cm ratio. The mortarsspecimens were subjected to 5％ magnesium sulfate for 700 days. The weight loss,compressive strength, and expansion strain were used to evaluate the performance of themortars to resist magnesium sulfate attack. From the test results, the mortars specimens madewith mineral admixtures either silica fume or metakaolin had weight loss, length change, andcompressive strength loss greater than those of mortars without mineral admixtures.
Ahmed M.Diab Abd Elwahab M.Awad Hafez E.Elyamany Abd Elmoty M.Abd Elmoty
Structural Engineering Department,Alexandria University,Egypt
国际会议
南京
英文
445-454
2008-10-13（万方平台首次上网日期，不代表论文的发表时间）