Mechanical resistance of reinforced concrete beams strengthened by waste fishing net hybrid fiber-reinforced cementitious composites

Abstract

This study experimentally investigates the flexural-shear performance of reinforced concrete (RC) beams strengthened with waste fishing net (W) hybrid fiber-reinforced cementitious composites (W-FRCCs), which has rarely been conducted in recent research and has not yet been addressed in existing standards and codes. Three-point bending tests are conducted on four series of RC beams strengthened and non-strengthened with W-FRCCs. Three types of strengthening layers are used to reinforce the RC beams, and five flexural parameters are evaluated. Although all RC beams failed under flexural-shear failure, using mortar with W textile (WT) and W short fiber (WF) is more effective in reinforcing conventional RC beams compared with using mortar and mortar with WT. The strengthening layers using mortar-reinforced WT and WF resulted in better performances compared with conventional RC beams. Additionally, the WT contributed significantly to load bearing from the initial stage up to a deflection of 4 mm, whereas the WF became effective beyond a 4-mm deflection due to the significantly higher stiffness and rigidity of the epoxy-treated WT compared to those of the WF. Moreover, using W-FRCCs in strengthening RC beams resulted in smaller crack widths compared with the case of non-strengthened RC beams because WF and WT delayed crack initiation and distributed stress more effectively. This strengthening method presents promising potential owing to the sustainable use of W, which can increase recycling rates and mitigate plastic pollution.