Flexural Performance of PVA FRCC Beams under Quasi-static and Low-velocity Impact Loads

摘要

The objective of this paper is to estimate effects on the polyvinyl alcohol (PVA) fiber, and shear reinforcement on quasi-static and low-velocity impact load resistances of concrete beams. By repeated dropping a 270 kgf weight on the specimens from a height of 1.8 m, low-velocity impact load was applied. Load-deflection curve, peak load value, and crack pattern were used for analyzing the results of the static load tests. The maximum number of blow, crack patterns, and time-deflection curves at the first drop stage were used for analyzing the results of the impact load tests. Both static and impact resistances or reinforced concrete beams enhance by PVA fiber with improvement of tensile strength and ductility of concrete matrix. Also, by the PVA fibers in reinforced concrete beams, the required amount of shear reinforcement to prevent shear failure mode can be reduced. Since major contribution of fiber reinforcing can be represented in terms of increased toughness and beneficial resistance of local spalling, the fiber reinforced concrete RC beams showed correspondingly larger endurance of drop blows and smaller crack width under low velocity impact loadings. Under the impact loads, the partially placed specimens with PVA FRCC can show similar impact load resistances compared to the fully placed specimen. However, in order to apply FRCC partially to the specimens maintaining their impact load resistance, the FRCC should be applied not only in tensile face but also in compressive face.