285 / 2022-11-03 18:36:49

Finite element analysis of heavily-corroded reinforced concrete beam strengthened by high-strength Engineered Cementitious Composites

ECC,SHCC,Finite Element Analysis (FEA),Flexural strengthening,Reinforced concrete beam

Reinforced concrete (RC) structures are widely used in civil engineering, while the severe corrosion of steel rebars can greatly affect their load-carrying capacity. Existing methods for dealing with heavily-corroded rebars (such as rebar-planting) are time-consuming and labor-intensive. Therefore, researchers are seeking other alternative methods. Exhibiting excellent crack resistance ability and high toughness, high-strength Engineered Cementitious Composites (HS-ECC) have been used in repairing pavements and dams. Recently, (Chen et al. 2018) reported that HS-ECC have the potential to fully recover the load-carrying capacity of RC beams with heavily-corroded steel rebars. Based on the test results from the literature, this study aims to use a finite element approach to explore the key parameters affecting the repair effectiveness of the HS-ECC patch for RC beams with heavily-corroded steel rebars.



Finite element models (Fig.1) were established to explore the effectiveness of HS-ECC patch on heavily-corroded RC beams under four-point bending. The specimens REF-F and REF-R represent two types of reference beams (without patching) with full and reduced rebar sections, respectively; while B40 and B55 represent two different bond lengths (4.0D and 5.5D) of the patch (Fig.2). The steel rebar with reduced section is a continuous Y20 rebar with a 50 mm-long reduced area with a diameter of 17.3 mm (Fig.1), which represents a 25% nominal area loss. Generally speaking, the simulation results have good agreement with the test results, especially in terms of the peak load (Fig.3, Fig.4, Fig.5). Additionally, some key parameters affecting the repair effectiveness of HS-ECC patch were systematically discussed, including the tensile strength of ECC, the ultimate tensile strain of ECC, as well as the bonding length between ECC and steel rebar.



Results showed that the heavy corrosion of steel rebars can significantly affect the load-carrying capacity of RC beams, while the proposed HS-ECC patching approach has satisfactory repair effectiveness when the nominal area loss for steel rebars is no more than 25%. To ensure the repair effectiveness, the tensile properties of HS-ECC material and the bond length have to fall within the suggested ranges. Overall considering the cost and time, the repair method mentioned in this paper is superior to the existing method. The findings of this study can support future repair applications using HS-ECC in practical engineering.