Role of silica fume in producing high strength self-compacting concrete

Abstract

Self-compacting concrete has a very important role in the construction of tall structure, because such structures are designed for higher grade concrete as well as higher grade of steel, with less dimensions of structural components. The main execution difficulty of normal concrete was raised due to congestion of reinforced in the structural components, where self-compacting concrete (SCC) is compacted under its own weight without compaction or vibration as well as it has excellent fresh state properties without segregation and bleeding. For present experimental work, first to adopt optimum dosage of superplasticizer is 2.5% and w/c ratio is 0.28 by trial and error method, with accepting fresh properties of SCC results. Later the study is carried by replacement of silica fume with cement 4, 8, 12, and 16% of silica fume by trial and error method. The results obtained by replacement of 12% of silica fume for 7 days compressive strength is 40.1 N/mm2 and for 28 days compressive and split tensile strength are 72.6 and 6.9 N/mm2, respectively. For a proportion of 2.5% superplasticizer, 0.28 w/c, 12% of silica fume, 506 kg/m3 of cement, 700 kg/m3 of fine aggregates and 833 kg/m3 of coarse aggregates were produced very good compressive strength and split tensile strength, and the trial and error SCC mix design can be adopted for above M70 grade concrete.