CFRP Materials for Restoration of the Bearing Capacity of RC Beams With Damaged Rebar

Abstract

Corrosion of the rebar in reinforced concrete (RC) structures is a critical concern, compromising their reliability and long-term operation. Carbon fibre–reinforced polymer (CFRP) tapes are widely used for strengthening RC structures due to their superior properties such as light weight, high strength and ease of application. The study aims to investigate the effectiveness of using CFRP-bonded tapes as a flexural repair system for RC beams, considering the effect of pre-repair damage to rebar. The experimental programme consisted of testing two unstrengthened control specimens without damage and two samples with 50% damage to the rebar, strengthened with CFRP materials. To maximize the effectiveness of CFRP materials for strengthening, a comprehensive understanding of their behaviour, particularly during the later stages of loading, is essential. The purpose of this study is to fill this gap of knowledge with the use of innovative remote monitoring techniques: submicron indicators and digital image correlation (DIC). By cross-verifying results through two independent approaches, any potential biases or errors inherent were mitigated, leading to more robust and reliable outcomes of the experimental research. A comprehensive analysis of the obtained experimental data, also validated through theoretical calculations, has shown that the proposed repair method ensured a 95% recovery of the initial bearing capacity. Also, notable changes in the behaviour of samples were observed with increased strains and deflections compared to control samples. Remarkable possibilities of the DIC method enabled monitoring of the stress–strain state of the full-scale samples until the destruction stage. The findings of the research are significant in the engineering application, as it deepened the understanding of CFRP strengthening techniques and can potentially broaden the use of CFRP tapes in strengthening corroded RC beams.