ABSTRACT
Chloride penetration in reinforced concrete is a significant issue triggering corrosion of steel reinforcements, compromising the structural integrity of concrete structures. Non-destructive testing (NDT) techniques and structural health monitoring (SHM) systems play an important role in detecting such deteriorations facilitating interventions to prevent structures from reaching a critical stage. The integration of near/short wave-infrared (NIR/SWIR) hyperspectral imaging into SHM techniques represents a significant advancement, offering a non-contact solution for chloride inspection. This study investigates the effectiveness of hyperspectral imaging (HSI) for identifying chloride in plain concrete samples with varying salt concentrations of 0%, 1%, and 3.5% in the range of 950 to 2500 nm. The samples undergo simulated chloride penetration through 48-hour dry-wet cycles. The results reveal that the presence of chloride crystals is captured by reflectance changes near 1450 nm and 1950 nm. Additionally, the formation of Friedel’s salts is observed, noticed earlier at higher concentrations where the exposure to chloride is enough for the reaction to occur.
