Shear Behavior of Reinforced Concrete Beams Strengthened by Epoxy Mortar Panel with Steel Fibers

Abstract

The purpose of this study was to develop a new strengthening material that increases the shear strength and improves the deformation capacity of reinforced concrete (RC) beam members. A new composite material named epoxy mortar with steel fiber (EMSF) was prepared by inserting steel fibers into an epoxy mortar to provide the new strengthening material with high strength-toughness characteristics. In this study, materials and structural tests were employed. The materials tests assessed the influence of the volume percentage and the length of steel fiber on the tensile strength and toughness capacity of the composite material, EMSF. The structural tests help determine the influence of the EMSF panel type and thickness on the shear capacity and shear failure mode of strengthened RC beam members. The results of the two test groups are summarized as follows: 1) the results from the material tests indicated that the EMSF panel with 35 mm steel fibers exhibited high tensile strength, and the EMSF panel with both 35 mm and 50 mm steel fibers showed good toughness capacity; 2) the RC beam strengthened by an EMSF panel with short (35 mm) fibers possessed the highest shear strength, 3) the RC beam strengthened by an EMSF panel with both short (35 mm) and long (50 mm) fibers exhibited improved deformation capacity; and 4) a shear strength equation was derived from the equilibrium of the cracked RC beam members and is in good agreement with the test results.