Compressive behavior of FRP-confined normal concrete or seawater sea-sand concrete containing FRP-bar recycled coarse aggregates

• Published in: Engineering structures 2024-03, Vol.303, p.117500, Article 117500
• Main Authors: Gao, Z.Y., Zhang, S.S., Lin, Guan, Yu, T., Nie, X.F.
• Format: Article
• Language: English
• Subjects: Axial compression; Confinement; FRP waste recycling; Recycled aggregate; Seawater sea-sand concrete
• ISSN: 0141-0296; 1873-7323
• DOI: 10.1016/j.engstruct.2024.117500

Fiber-reinforced polymer (FRP) waste has become an environmental concern owing to the non-biodegradable nature and widespread use of FRP composites. Cutting the disposed waste of FRP bars into small pieces (referred to as FRP-bar recycled aggregate or FRP-RA) and replacing natural coarse aggregate in concrete with these pieces is considered a promising solution for recycling FRP waste. Owing to its excellent corrosion resistance, FRP-RA can be used as a raw material for the production of seawater sea-sand concrete (SSC). This study investigated the axial compressive behavior of FRP-confined normal concrete (NC) or SSC containing FRP-RA. The FRP-RA was cut from glass FRP (GFRP) bars of different diameters. Axial compression tests were conducted on 96 specimens. The specimens were designed with the following parameters: the type of concrete (NC and SSC), natural coarse aggregate replacement ratio (0%, 33%, 66%, and 100% by volume), thickness (1-layer and 2-layer), and type (carbon FRP and GFRP) of the FRP jacket. The test results indicated that the presence of the FRP-RA reduced the compressive strength and elastic modulus of the concrete. FRP confinement significantly enhanced the compressive strength and ultimate axial strain of the concrete with FRP-RA. No discernible difference was observed between SSC and NC with respect to FRP-RA. Finally, a widely adopted stress-strain model for FRP-confined NC was first evaluated using the test results, and a modified stress-strain model was then proposed for more accurate predictions. •The use of waste FRP bars in small pieces as coarse aggregates in concrete is a promising solution for recycling FRP waste.•FRP confinement can significantly enhance the compressive behavior of concrete with FRP-bar recycled aggregates (FRP-RA).•Test results of 96 cylindrical FRP-confined concrete specimens with FRP-RA were analyzed and presented.•A model is proposed to predict the axial compressive behavior of FRP-confined concrete with FRP-RA.