Flexural Characteristics of Pine Needle Reinforced Concrete

Abstract

The utilization of Fiber Reinforced Concrete (FRC) as a structural material is steadily on the rise. Conventional concrete is characterized by its brittleness, displaying a flexural strength that falls within the range of 10-15% of its compressive strength. Incorporation of fibers into concrete enhances various mechanical properties, including tensile strength, flexural strength, and ductility. An advantageous feature of fiber-reinforced concrete is its capacity to consider cracked concrete below the neutral axis in the cross-section of a beam to some extent. Stress-strain diagram proposed by Beshara proves valuable in integrating the effect of FRC on the tension side, an aspect previously neglected due to the inherent weakness of PC in tension. In current investigation mix design of 1:4:2:0.8 (cement: sand: aggregate: water) is used for preparing PC. Pine needle fibers hybrid lengths of 37mm, 50 mm and 62.5 mm are used for preparation of PNFRC. Improvement observed in energy absorption by 2.5 times, toughness index 5 times, maximum deflection up to 12mm and decrease in MoR observed by 34%. Ductile behaviour also observed with respect to the reference specimens. In general, pine needle fibers has the potential to be used in cement concrete composites for different structural applications.