Use of silica fume and recycled steel fibers in self-compacting concrete (SCC)

•Effects of silica fume and the recycled steel fiber experimentally investigated.•The hardened properties were characterized by using compressive, tensile, flexural, and impact tests.•The fresh properties were determined by using the slump flow test and V-funnel test.•Combined effects of silica fume and the recycled steel fiber improved the mechanical properties and impact resistance. This paper aims to investigate the effects of replacing cement with silica fume in the reinforced self-compacting concrete with recycled steel fiber and study its mechanical properties and impact resistance. To characterize mechanical properties and impact resistance, 144 specimens with different fiber volume fractions of 0.25%, 0.5%, and 0.75% were experimentally tested. Mechanical properties of specimens were characterized with regard of compressive, splitting tensile, and flexural strengths. Concerning the obtained large experimental database, an analytical analysis was performed by using regression analysis to investigate the correlate between the impact and mechanical properties of self-compacting concrete reinforced with recycled steel fibers. In addition, the correlation between the mechanical properties of specimens and the content of the replaced cement with silica fume was also examined. The results revealed that the combined effects of silica fume and recycled steel fiber improved the mechanical properties and impact resistance of specimens. Moreover, linear equations were also developed to correlate mechanical properties and impact resistance of specimens with a high coefficient of determination.