This research aims to shed light on the effect of steel fiber shape, length, diameter, and aspect ratio on the mechanical properties of slurry infiltration fiber reinforced concrete (SIFCON). This study comprised of casting and testing three groups of SIFCON specimens with 6% fiber volume fraction. The first group was reinforced with micro steel fiber, other reinforced by hook end steel fibers, while the last group of specimens reinforced by mixing two shape of steel fiber as hybrid fiber (3% micro steel fiber +3% hook end steel fiber). Silica fume was used as a partial replacement (10%) by weight of cement. 3.7% super plasticizer was used to make the slurry liquid enough to penetrate through the fiber network, while the w/c ratio kept constant at 0.33. It was found from the results achieved that the compressive strength, static modulus of elasticity, splitting tensile strength and toughness are extremely affected by the geometry of fibers because the network of fibers formed and their density depends on the size and shape of fibers. Where the values of micro steel fibers are far outweighing the values of hooked end fibers. It was also deduced from empiricism results that combining long and short fibers gives excellent results.

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This article is an experimental study of the efficiency after fire exposure of slurry infiltrated fiber concrete (SIFCON) columns. The aim of this paper is to present a comprehensive study of the fire effect on the stiffness, ductility, and energy absorption capacity of axially loaded SIFCON columns and to inspect the effect of hollow ratio and cross section shape on the energy dissipation ability, ductility, and stiffness features of the post-fire behavior of these columns. Hybrid fibers were used to cast SIFCON columns with 6% fiber ratio (3% hooked end fiber + 3% straight micro fiber). The results showed that the cube compressive strength decreased by 25.1% and 53% when exposed to fire at a temperatures of 600 and 900 C, respectively. The results obtained revealed that after exposure to fire, the indices values of displacement ductility are not strongly impaired and it has been shown that the assessment of the energy dissipation ability is more relevant in this situation. Whereafter fire exposure at 600 C, the SIFCON columns lost about 11%-31% of the energy absorption capacity and about 39%-57% after fire exposure at 900 C. In comparison, after fire exposure, the secant and initial stiffness greatly degraded and the reduction percentages became higher with a rise in fire temperature from 600 to 900 C.

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