Improving the impact resistance and dynamic properties of jute fiber reinforced concrete for rebars design by considering tension zone of FRC

Abstract

The demand for the safety of structures against severe loading (e.g. impact) is increasing day by day. Structures safety is generally associated with the materials used for construction. To achieve economy without compromising the strength requirements, fibers are being used to enhance concrete’s mechanical properties and impact resistance. However, the effectiveness of natural fibers in concrete under impact loading needs to be investigated in details. In this study, the behavior of jute fiber reinforced concrete (JFRC) under impact and dynamic loadings is experimentally investigated. Small slab panels of plain concrete (PC) and JFRC, without and with steel reinforcements, are tested for flexural strength and impact resistance. A simplified drop-weight test is used to find the impact resistance in the laboratory. Reinforcement in slab is designed using tension zone of FRC and its value is compared with ACI design. Dynamic elastic modulus, resonance frequencies and damping ratios are found for different specimens as per ASTM standard C215. Basic mechanical properties are also determined. Fracture surface is examined at micro level through scanning electron microscope (SEM) under impact and flexure loads. Significant improvement in impact resistance of concrete is seen by incorporation of jute fibers. Impact resistance of JFRC is enhanced up to 6 times as compared to PC. Dynamic elastic modulus and damping ratio are also enhanced by 68% and 100%, respectively. Flexure and split-tension strengths are increased by 20% and 8%, respectively. It is concluded that about 28% steel reinforcement in slabs can be reduced by the use of short jute fibers in concrete.