Workability and mechanical behavior of steel fiber reinforced self-compacting concrete with supplementary cementitious materials

The use of additives as supplementary cementitious materials (SCM) from waste materials in concrete helps to improve its properties and protects the environment from hazardous impacts. This study is focused to use waste materials like silica fume and fly ash with steel fibers (SFs) in production of SCC. Two mixes with 5%SF&15%FA and 10%SF&15%FA were used. The dosage of steel fibers with aspect ratio 20 was used in the dosage of 0.1, 0.15, and 0.2% by volume of concrete. To test fiber's impact on workability, a lower aspect ratio is chosen. From test results, it was observed that lower dosage of additive shows better performance of SCC both at fresh and hardened state. Significant improvement in the flexural strength of concrete mix containing 0.15% SFs, 5%SF&15%FA was recorded. In addition the specimens with the steel fibers during split tensile and bending test did not split completely in two pieces at collapse due to the presence of fibers, which act as locking medium in concrete matrix. This indicates some sort of ductile fracture and sign of impending warning time before the complete failure of high-strength SCC.