Fiber Distribution And Experimental Study On Flexural Behavior Of Steel Fiber Reinforced Concrete

Concrete has many outstanding advantages, such as high compressive strength, easy available raw materials, relatively simple for construction and so on. However, the low tensile strength and brittle fracture greatly influenced the practical engineering application. Fiber reinforced concrete(FRC) compared with plain concret significantly improve the tensile strength and improve the crack resistance and toughness through resisting the emergence and development of the internal micro-cracks in concrete. At present, steel fiber reinforced concrete (SFRC) is the most widely used FRC.Currently flexural toughness is widely used as a measure of toughness of FRC. In this paper, experimental research on the flexural toughness of SFRC is carried out. The toughness of SFRC are analyzed using DIN and RILEM TC162-TDF, respectively. Fiber content, concrete strength, fiber number on the cross section and fiber distribution have been considered to analyze the influences of steel fiber on the toughness of concrete, and the corresponding math expression has been proposed based on the study of fiber distribution for twelve fiber types. Meanwhile, predictive equations are suggested for evaluation of the flxural strength and fiber distance by fiber number per unit volume. In addition, the stress-crack opening relationship (σ-ω) and simplied tension model is obtained using inverse analyse based on the flexural load-deflection curves. The results indicate that the energy absorption and equivalent flexural stress increase with the increasing fiber content; the beams with high fiber content but low toughness is also present; the toughness of the beam can be significantly affected by the fiber distribution on the cross section; the proposed equations can be used to forecast the fiber number and fiber distance.