Novel FRP micro-bar reinforced UHPC permanent formwork for circular columns: Concept and compressive behavior. (1st April 2022) - Zeng, Jun-Jie
Abstract: In this study, a novel form of tubular permanent formwork that is made of ultra-high-performance concrete (UHPC) internally reinforced with fiber-reinforced polymer (FRP) micro-bars (herein referred to as FRP-UHPC tubular permanent formwork or simply FRP-UHPC tubular column ) is developed. The axial compression test results of FRP-UHPC tubular columns with and without in-filled concrete are presented and discussed. Effects of the FRP micro-bar spiral pitch, the steel fiber addition in the UHPC, the tube thickness and the presence of external FRP confinment are investigated. The test results confirmed that the FRP-UHPC tubular columns have an excellent compressive strength, and the strength and ductility of existing concrete columns jacketed with an FRP-UHPC composite tube are substantially enhanced due to the confinement and axial contribution of the FRP-UHPC tube. The proposed FRP micro-bar-reinforced UHPC composite tubes are attractive in structural applications as pipelines or permanent formworks for columns, as well as external jackets (can be prefabricated in the form of two halves of composites tubes) for strengthening deteriorated reinforced concrete columns.