Interfacial behaviour and shear performance of polarized CFRCM-strengthened corroded RC continuous beams

Abstract

This paper investigates the shear performance of corroded reinforced concrete (RC) continuous beams strengthened with polarized carbon fabric reinforced cementitious matrix (CFRCM) plates within an innovative impressed current cathodic protection-structural strengthening (ICCP-SS) repair system. A trilinear cohesive law was developed based on pull-out tests with varying bond lengths to characterize the carbon fabric (CF)-cementitious matrix interface behaviour. Finite element analysis (FEA) incorporating the proposed interface model was conducted on five RC beams to validate critical parameters including failure mechanisms, moment redistribution, load capacity, and shear strength. The interfacial shear stress distribution and CF tensile stress were analyzed. A parametric study comprising 44 numerical models was conducted to evaluate the effects of steel rebar corrosion rate, CF mesh layers, and charge density on shear capacity. The experimental and numerical results were compared with theoretical predictions using ACI 549.4R-20 and the strut-and-tie model (STM). It was concluded that the layered modelling approach for polarized CFRCM composites effectively captured the mechanical response of strengthened specimens. Specifically, while anodic polarization of the first CF layer through ICCP modified the interfacial shear stress distribution, it achieved more uniform interlayer bond behaviour, partially compensating for material degradation. Moreover, despite initial strength reduction due to anodic polarization, the ICCP-SS system significantly enhanced structural durability. Additionally, theoretical predictions using ACI 549.4R-20 showed conservative estimates, while the STM incorporating tensile constitutive behaviour provided more accurate predictions.