Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | Department of Civil and Environmental Engineering | en_US |
| dc.contributor.advisor | Teng, Jin-guang (CEE) | en_US |
| dc.contributor.advisor | Lin, Guan (CEE) | en_US |
| dc.creator | Li, Xinyun | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/14433 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | en_US |
| dc.rights | All rights reserved | en_US |
| dc.title | Behaviour of wavy-shaped FRP-UHPC hybrid rebars | en_US |
| dcterms.abstract | Fibre-reinforced polymer (FRP) rebars have seen increasing adoption in concrete structures to replace steel rebars due to their advantages of high strength-to-weight ratio and excellent corrosion resistance. However, FRP rebars have much weaker compressive performance than their tensile performance due to fibre micro-buckling under compression. A novel hybrid rebar, featuring an outer FRP tube, a central FRP rebar, and an annular layer of ultra-high performance concrete (UHPC), has been proposed by J.G. Teng and his associates at The Hong Kong Polytechnic University (PolyU) to address this issue. The central FRP rebar is well supported by the UHPC and the latter is well confined by the outer FRP tube when the hybrid rebar is under compression. Therefore, global buckling of the rebar and fibre micro-buckling in the central FRP rebar can be suppressed or delayed. In the initial proposal by Teng and associates, the outer FRP tube had a uniform cross-section in the longitudinal direction (referred to as a uniform FRP tube hereafter), and as a result, the bond between such hybrid rebars (referred to as uniform hybrid rebars hereafter) and the surrounding concrete, as well as that between the FRP tube and the inner UHPC, is less than satisfactory. Against this background, this Ph.D. research project was concerned with a new form of hybrid rebars with a wavy shape for the FRP tube in the longitudinal direction. The wavy-shaped surface introduces mechanical interlocking between the hybrid rebar and the surrounding concrete, which is expected to substantially enhance the bond performance. | en_US |
| dcterms.abstract | The initial phase of this Ph.D. research programme explored the manufacturing method of wavy-shaped FRP tubes with the filament winding technology. The resin burn-off test and the digital image processing method were employed to determine the fibre volume fractions of the fabricated wavy-shaped FRP tubes at different locations. Split disk tests and internal air pressure tests were conducted to examine the hoop elastic moduli of wavy-shaped FRP tubes. | en_US |
| dcterms.abstract | The second part of this Ph.D. research programme focused on the compressive performance of FRP-confined UHPC/ultra-high performance fibre reinforced concrete (UHPFRC) with a compressive strength of over 180 MPa. The experimental investigations on FRP-confined UHPC/UHPFRC under axial compression were first conducted. The existing predictive models which had been proposed for FRP-confined normal strength concrete (NSC) and UHPC/UHPFRC were then evaluated and developed. | en_US |
| dcterms.abstract | The third part of this Ph.D. research programme included experimental studies on the compressive performance of wavy-shaped hybrid rebars under monotonic axial compression and cyclic axial compression. The test results indicated that the proposed wavy-shaped hybrid rebars exhibited compressive strengths and ductility levels comparable to uniform hybrid rebars under either monotonic or cyclic axial compression. An improved stress-strain model for FRP-confined UHPC under cyclic axial compression was developed, which was used subsequently to accurately predict the cyclic axial compressive behaviour of wavy-shaped hybrid rebars. | en_US |
| dcterms.abstract | In the final part of this Ph.D. research programme, pull-out tests were conducted to investigate the bond performance of wavy-shaped hybrid rebars. The test variables included the FRP confinement level, the bond length, and the type of FRP rebars. The test results indicated that the adoption of wavy-shaped FRP tubes significantly enhances the bond performance between wavy-shaped hybrid rebars and surrounding concrete. | en_US |
| dcterms.extent | xxix, 326 pages : color illustrations | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 2026 | en_US |
| dcterms.educationalLevel | Ph.D. | en_US |
| dcterms.educationalLevel | All Doctorate | en_US |
| dcterms.accessRights | open access | en_US |
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