Influence of stainless steel fibres on the mechanical properties of self-compacting ultra-high-performance geopolymer concrete
Islam Eltantawi, M. Neaz Sheikh, Muhammad N.S. Hadi
Abstract
This study investigates the impact of stainless steel fibres (SSF) on the flowability and flexural, compressive, and direct tensile strengths of ambient-cured self-compacting ultra-high-performance geopolymer concrete (SCUHPGC). Two different types of straight SSF were added to the SCUHPGC mixtures: short fibres (S) with a length of 6 mm and aspect ratio of 30 and long fibres (L) with a length of 13 mm and aspect ratio of 65. It was observed that the flowability of SCUHPGC mixtures decreased with an increase in the volume fraction of SSF. However, the addition of SSF improved the flexural strength, compressive strength, and direct tensile strength of the SCUHPGC mixtures. Significant improvements in the mechanical properties were achieved with the addition of 2 % by volume of either short or long SSF. The addition of 2 % hybrid SSF fibres (0.5 % of short fibres and 1.5 % of long fibres), identified as the optimal hybrid fibres, achieved the highest improvement in the mechanical properties with a slight decrease in the flowability of SCUHPGC. The flowability of the SCUHPGC mixture decreased from 230 mm to 200 mm, but the flexural, compressive, and tensile strengths of the SCUHPGC mixture increased from 9.6 MPa to 24.2 MPa, 132.7 MPa to 173.0 MPa, and 4.9 MPa to 9.2 MPa, respectively, for the inclusion of the optimal hybrid fibres. Scanning electron microscope investigations revealed that the crack-bridging mechanism of SSF contributed significantly to the improved mechanical properties of SCUHPGC. • SCUHPGC is developed and evaluated in this study. • GGBFS, FA, MS, and SSF mixed with SS and SH are used to develop SCUHPGC. • Volume fraction of SSF influences the mechanical properties of SCUHPGC. • Hybrid SSF improves the mechanical properties of SCUHPGC. • SEM analysis showed a strong bond between the SCUHPGC paste and SSF.