NDT methods for monitoring internal swelling reactions in concrete

Non-destructive testing (NDT) methods are key tools for monitoring concrete structures, as they offer the advantage of detecting structural defects over time without causing additional damage. Additionally, internal swelling reactions have been identified as pathologies responsible for structural defects in many structures worldwide, often leading to demolition and expensive repairs. It is therefore particularly important to develop the application of NDT methods for monitoring damage in the affected structures. Based on this context, this research aims to study the application of NDT methods in monitoring damage caused by internal swelling reactions including alkali-silica reaction (ASR) and delayed ettringite formation (DEF). To this end, control and damage-induced specimens were cast and stored fully immersed in water at 380C for monitoring. The monitoring was carried out using NDT methods including resistivity, linear vibration and ultrasonic pulse velocity (UPV). The results showed that resistivity can effectively monitor alkali leaching in concrete affected by ASR and DEF. Linear vibration was capable of monitoring all stages of ASR and DEF, including damage acceleration, stabilization, and recovery. UPV, however, showed lower sensitivity to damage caused by ASR only. The findings related to resistivity and linear vibration can be used to develop predictive relationships and enhanced monitoring strategies for structures affected by ASR or DEF.