Effect of Silica Fume on Mechanical and Fresh Properties of High Strength Self Compacting Concrete

This study presents the effect of incorporating silica fume (S.F) on the mechanical and fresh properties of high strength self-compacting concrete (HSSCC) for a constant water/binder ratio of 0.28. Fly Ash replacement was kept constant at 25 %. S.F mixtures with cement replacement of 7.5, 10, 12.5 and 15 % were designed for high strength and slump flow range of 650 mm to 700mm. From the results, it was observed that 12.5 % replacement level was the optimum level in terms of compressive strength. Beyond 12.5 % replacement levels, the strength was decreased but remained higher than the control mixture. Compressive strength of 88Mpa was achieved at 12.5 % replacement for 28 days while 101.21Mpa was obtained at 90 days .Splitting tensile strength values have also followed the same trend. Slump flow, T 500, V funnel and L box tests were carried out in order to investigate the fresh properties. In workability tests S.F concretes showed lower values compared to control. This investigation has shown that the local S.F has the potential to produce high strength self-compacting concretes.