Effect of Crimped and Hooked End Steel Fibers on the Impact Resistance of Concrete

Abstract

It is well known that concrete is characterized by its high compressive strength, yet its brittle mode of failure is considered as a drawback of high strength concrete when it is subjected to impact and dynamic loads. This study aims to investigate the impact resistance of fibre reinforced concrete (FRC), incorporated with steel fibres at various dosages. For this, a drop weight test was performed on the 28 days cured plain and fibre reinforced concrete samples as per the testing procedure recommended by ACI committee 544. Crimped and hooked end steel fibre of length 50 mm and an aspect ratio equal to 50 was added to concrete in different proportions i.e. 0%, 0.5%, 1.0% and 1.5% with water cement ratio of 0.42. From the test results, it was proved that the (FRC) was effective under the impact loads thus improving the impact resistance. Also, the reduction of strength under impact load in each specimen for every three blows was determined by ultrasonic pulse velocity (UPV) test. Further, a statistical correlation between (UPV) and number of blows under impact load was developed using regression analysis. The developed regression model predicts the reduction in strength of concrete under impact load accurately.