Evaluation on Expansion of Concrete due to DEF and ASR by using Sonic-IR method

Concrete deterioration caused by delayed ettringite formation (DEF) and alkali-silica reaction (ASR) is characterized by internal expansion and cracking. These phenomena are difficult to distinguish based on external crack patterns, and early detection remains a major challenge. Conventional assessment methods, such as laboratory accelerated test with core sampling, gives the inconvenience with time-consuming procedures. Additionally, the quick and accurate method for evaluating the expansion risk/potential is still unavailable. This study investigates the application of Sonic Infrared (Sonic-IR) technique, which is a non-destructive thermal imaging method that visualizes internal cracks by detecting heat generated through ultrasonic-induced friction and stress concentration at defect inside the targeted material. Sonic-IR offers the enhanced sensitivity to microcrack and minimal surface damage. The proposed method shows the promising utilization for early detection and evaluation of expansion associated with DEF and ASR in existing concrete structures.