Fire-resistant FRP rehabilitation schemes for RC columns

Abstract

This thesis investigates various fibre-reinforced polymer (FRP) schemes at ambient and after elevated temperature exposures, setting their limits and exploring new solutions and approaches for dealing with FRP fire-resistance issues. To achieve this objective, an extensive experimental program was conducted, comprising more than 1,000 specimens tested using different FRP strengthening schemes under ambient conditions, various elevated temperature levels, and fire exposures, including wrapped and unwrapped concrete cylinders, coupons, dog-bone specimens, mortar cubes, concrete beams, pull-out tests, and full-scale reinforced concrete (RC) columns. Based on the previously mentioned dilemma, this research aims to fill these gaps by investigating the potential solutions for the degradation of FRP jacketing under fire conditions and quantifying the appropriate FRP system needed for post-fire rehabilitation. The presented work demonstrates that the approaches adopted by the international design guidelines are considerably conservative for FRP-wrapped vertically loaded elements, upon which more practical design recommendations are presented herein. The work also highlighted the limits and drawbacks of using the TRM system, as the system will typically crack beyond 400 °C, promoting fabric oxidation and local fibre damage. On the other hand, a significant enhancement was achieved using the ASJ scheme, and even after epoxy decomposition, there was no need for the traditional complex steel mechanical anchor configuration. This was confirmed by fibre rupture, absence of anchor dislocation, and cracks near the anchor upon failure, with an average compressive strength enhancement ratio of 1.55 and 1.84 at 380 °C for the epoxy-based and cementitious-based ASJ configurations, respectively. Moreover, the SBM demonstrated superior performance with an average compressive strength enhancement ratio of 2.83 and 1.89 for 500 °C and 650 °C exposures, respectively, with no need to reapply the jacketing work. Finally, the applicability of SBM FRP was validated through a full-scale RC columns investigation, the detailed outcomes of which are presented in the thesis.

Date of Thesis submission	2026
Original language	English
Awarding Institution	Western Sydney University
Sponsors	Australian Government Research Training Program Scholarship
Supervisor	Jason Jiang (Supervisor) & Zhong Tao (Supervisor)