Experimental Study of the Shear Behavior of RC Beams Strengthened with High-Performance Fiber-Reinforced Concrete

Abstract

In this study, the efficacy of strengthening of reinforced concrete (RC) beams in shear by utilizing high-performance fiber-reinforced concrete (HPFRC) was explored. The shear strengthening was achieved by epoxy bonding of prefabricated HPFRC strips or plates onto the beams. The beams were strengthened utilizing two different strengthening schemes: (i) plates side strengthening (ii) vertical strips applied at shear critical sections. The behavior of the two configurations was compared to the behavior of non-shear reinforced and shear-reinforced RC beams. The high-performance concrete (HPC) utilized contains 1.5% of steel fibers per volume of HPC mortar and is known as HPFRC. Parameters determined were the flexural strength and compressive strength of HPFRC mortar. The obtained results revealed that HPFRC realized a 28-day flexural strength of 20 MPa and a compressive strength of 108 MPa. Moreover, HPFRC strengthened RC beams experienced an increased in strength capacity of about 50% for plates and 36% for vertical strips compared to the RC beams with no stirrups. The results for HPFRC strengthened beams with plates were superior compared to those of the stirrup-reinforced beams, whereas the results of HPFRC strips strengthened beams were almost identical to the stirrup-reinforced beams. Also observed, was an improvement in the ductility of the beams with the best results achieved when employing HPFRC plates and strips.