The Statistical Approach to Study the Effects of the Size of Coarse Aggregates and Percentage of Steel Fiber on Mechanical Properties and Ductility of Concrete

Concrete members are reinforced by steel fibers to overcome their brittle nature. This paper is focused on the effect of percentage of fiber and the maximum aggregate size on mechanical properties of concrete samples such as compressive and tensile strengths, and ductility. The mean values of these quantities show that by increasing the reinforcement content to 0.66% and the size to 12.5 mm, there is a dramatic improvement on properties of samples. Also, they demonstrate that the size of coarse aggregate has more effect on improvement of the quantities in comparison to steel fiber content and changing the size and fiber content has more effects on ductility than mechanical properties. Statistical approach which considers standard deviations of experimental data, confirms that the gravel regardless of fiber content, leads to the highest improvement on properties with size of 12.5 mm. But the results show for volumetric steel fiber without considering aggregate size, is 0.33%. This clearly indicates the effect of data scattering on mean values of mechanical properties and ductility.