SILICA FUME CONCRETE: PRESENT RESEARCH SCENARIO

摘要

Silica fume addition to concrete leads to an increase in cohesiveness resulting in reduced workability. When silica fume is used as a cement replacement it results in reduced bleeding. There is very rapid consumption of silica fume over the first 28 days particularly within the first 7 days. However, regardless of the amount of silica fume added, reaction is always curtailed after an initial active period and even after long curing times, a large proportion is still unreacted. Silica fume concrete contributes most of the strength development in the time range from 3-28 days. Permeability of concrete is decreased by using silica fume as the number of large pores is reduced. The optimum dosage of silica fume that can replace cement in concrete have been observed to be between 10-20% of the cement content. Use of silica fume concrete has been widespread in the last few years and its behaviour is being studied in various research laboratories all over the world. Following are the areas in which further research needs to be undertaken for complete understanding of the silica fume concrete: 1. Optimum replacement level of silica fume from strength and durability considerations. 2. Effect of silica fume on plastic and drying shrinkage of concrete. 3. Behaviour of silica fume concrete subjected to alternate wetting and drying conditions, simulating marine exposure. 4. Microstructural investigations of silica fume concrete to predict its strength and durability characteristics.