Residual capacity of corroded reinforcing bars

TLDR

This paper presents an experimental investigation into the residual capacity of corroded reinforcing bars, examining the influence of type and diameter, and proposes a simple predictive equation. The study used accelerated and simulated corrosion tests on bare and concrete‑embedded bars to investigate how corrosion reduces reinforcement capacity. Results show that corrosion causes non‑circular, variable cross‑sections, leading to a rapid decline in residual yield and ultimate forces—especially for small or plain bars—though differences among bar types are not significant.

Abstract

This paper presents an experimental investigation into the residual capacity of corroded reinforcing bars. By performing both accelerated and simulated corrosion tests on bare bars and on bars embedded in concrete, the mechanism of the reduction of the capacity of corroded reinforcement was investigated. The influence of type and diameter of reinforcement on its residual capacity is discussed. The experimental results show that, due to local attack penetration, the residual cross-section of a corroded bar is no longer round and varies considerably along its circumference and its length. Although the force–extension curves of corroded bars are similar to those of non-corroded bars for up to 16% corrosion, their residual yield and ultimate forces decrease more rapidly than their average cross-sectional area and, therefore, their residual strength decreases significantly. Even though the residual capacity of corroded small diameter and/or plain bars reduces more than that of large diameter or ribbed ones, differences are not significant and can be neglected. Finally, a simple equation is proposed to predict the residual capacity of corroded reinforcing bars in practice.