Research on effect of the quantity and aspect ratio of steel fibers on compressive and flexural strength of SIFCON

SIFCON (Slurry Infiltrated Fiber Reinforced Concrete) is a composite which occur hardening of the matrix phase, consists of cement, water, silica fume, fine sand and water reducing plasticizer, and reinforced with high volume steel fiber (5–20%). The main difference from the high strength concrete (HSC) is the ductile behavior at failure. However the brittleness increases with the strength increase in HSC, SIFCON has a ductile behavior because of the high volume fiber content, low permeability, high durability. Despite fiber content is 2-3% in fiber reinforced concrete, fiber content may be ten times more in SIFCON and ductility is gained. This concrete is suggested to be used in military buildings against explosion, industrial grounds, airports and bridge feet. In this study, in order to investigate the compressive and flexural strengths of SIFCON, the slenderness and fiber ratio of steel fibers were chosen variable and the effects of these parameters on compressive and flexural strengths were investigated. In the study, steel fibers with slenderness of 40, 55, 65, 80 were used in 0, 4, 8 and 12% ratios. The water / binder ratio in the test samples was kept constant at 0.35, the silica fume ratio at 10%, and the plasticizer ratio at 1.5%. 7 and 28 days cured samples were subjected to compressive and flexural tests and the results were compared. As a result of the tests carried out, increases in both the compressive and flexural strengths of SIFCON specimens were determined with increasing fiber volume up to 8%. Strength reductions were observed at higher ratios. In cases where the fiber volume is too high, it is seen that the strengths were decrease due to the passage of mortar through the fibers. The highest strengths were obtained from fibers with a slenderness ratio of 80. Increase in the ratio of slenderness as well as increases in pressure and bending strengths have been found.