Monitoring of self-healing cementitious materials through contactless ultrasound

Abstract

Self-healing cementitious composites provide an alternative to labour-intensive and costly manual repairs. While a cementitious blend possesses an inherent ability to repair its own damage through autogenous healing, an enhancement of the self-healing capacity can be obtained through the inclusion of superabsorbent polymers (SAPs). The implementation of such innovative materials within the construction industry requires proper evaluation methods to ensure a safe environment for the user. Over the past few years, contact ultrasonic measurements have proven their potential in assessing the self-healing progress. The sensitivity of ultrasonic waves to the elastic properties of the material under study allows for a direct link with the regained mechanical performance. Additionally, its non-destructive nature enables in-situ evaluations. However, the coupling of the sensors leads to a certain variability in the obtained results, as the application of the sensors is not identical between measurements. In an effort to increase the reliability of the results, contactless ultrasound can be applied, which is investigated in the present research.