Flexural performance of reinforced concrete beams strengthened with FRP-reinforced geopolymer matrix: Numerical validation and parametric study

This study investigates the flexural performance of reinforced concrete (RC) beams strengthened by FRP-reinforced geopolymer matrix (FRGM) through a comprehensive numerical analysis. A two-dimensional (2D) finite element (FE) model is developed to simulate the behavior of the FRGM-strengthened RC beams, including the failure modes, load-deflection curves, and interfacial slips. The settings of the FE model, such as material properties, boundary conditions and interfacial bond properties between the FRGM and RC beams, are firstly validated by comparing the predicted results with the existing experimental data from previous publication. Subsequently, a parametric analysis involving 200 specimens is conducted to evaluate the effects of FRGM thickness, sectional area, location and type of the FRP rebar. The results indicate that the uniaxial compressive behaviors of geopolymer mortar and interfacial properties can be accurately described by the parabolic curve and bilinear traction-separation curve, respectively. The failure mode and load-carrying capacity of the specimens are primarily influenced by the axial strength of the reinforced FRP rebar. Additionally, the interfacial slip distributions transform from an inverse tangential shape to a sawtooth shape depending on the cracking pattern of the specimen.