Effectiveness of Premix Flat Crimped Steel Fibers as Reinforcement in Concrete Shear Applications: An Experimental Study

ABSTRACT The present study investigates the impact of Premix flat crimped steel (PFCS) fibers on the interface shear strength of concrete by conducting push-off tests on uncracked push-off specimens having varying fiber percentages (0.25 %, 0.5 %, 0.75 %, and 1 %) and interface shear reinforcement ratios (0 %, 0.76 %, and 1.13 %). The findings of this investigation reveal that the shear strength of the push-off specimens was significantly enhanced by an increase in the volume fraction of PFCS fibers. Test results showed about a 24 to 106 % increase in shear strength for specimens without reinforcement and a 28 to 84 % increase with shear rebars by increased PFCS fiber volume in concrete. The specimens reinforced with PFCS fibers generally exhibited enhanced ductility and improved crack control compared to control specimens without steel fibers. Modified Zia analysis was used to predict the shear strength of the push-off specimens. The shear strength values obtained from the modified Zia analysis for the push-off specimens in this investigation were in good agreement with the experimental findings. The average ratio between the Zia and experimental results was 0.97, with a coefficient of variance of 8.11. The interface shear strength models available in the literature and various design codes were evaluated for their predictive efficiency. Lastly, an analytical model was established by multiple linear regression analysis using the test data of the current investigation and subsequently validated by using available experimental data from the literature.