Corrosion state assessment of the rebar: Experimental investigation by ambient temperature and relative humidity

Abstract

One of the most crucial elements affecting the durability and stability of concrete construction is steel rebar corrosion. The primary cause of structural degradation in buried rebar is the generation of corrosion byproducts and the resulting volume expansion. The increased volume of the rebar within the concrete can exert tensile forces, leading to crack formation and concrete spalling. Therefore, the evaluation and prevention of rebar corrosion play a crucial role in ensuring the longevity and stability of structures, addressing concerns regarding their service life and structural integrity. The objective of this study is to measure and analyze the voltage potential at the target corrosion rate of the steel rebar. To achieve the precise target corrosion rate of the rebar, image processing was employed to measure the corrosion rate. By eliminating light reflection and noise, image processing enabled precise calculations based on the extracted corroded portions of the rebars. To evaluate the influence of temperature and relative humidity on the surface corrosion rate, voltage potential measurements were conducted. The results revealed that the voltage potential exhibited minimal sensitivity to temperature variations. However, it displayed a significant response to changes in relative humidity. Notably, smaller-diameter steel rebars exhibited increased variations in voltage potential in accordance with changes in the rate of relative humidity. This can be attributed to the small diameter and cross-sectional size of the steel, which facilitate electron mobility and, consequently, exhibit a high sensitivity to environmental changes.