Self-healing evaluation through ultrasonic measurements and 3D numerical simulations

¹ Department of Civil & Earth Resources Engineering, Graduate School of Engineering, Kyoto University, Katsura Campus, Nishikyo, Kyoto, Japan
² Department of Mechanics of Materials and Constructions, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium

^* Corresponding author: okude.nobuhiro.2w@kyoto-u.ac.jp

Abstract

Self-healing cementitious materials have gained attention as a resolution to costly and labourintensive manual repairs. Up to now, the regain in mechanical properties after healing is mostly evaluated through destructive tests, which are neither applicable for in-situ measurements, nor allow to monitor the healing evolution. Thus, a non-intrusive measuring technique is in demand, which could be found in the application of ultrasonic measurements (elastic waves in the ultrasonic frequency range). In this study, a method for evaluating mechanical recovery after healing is investigated by means of elastic waves. It comprises an assessment of the healing ability of mortars by experiments and numerical analysis. Experimental results show the decrease in wave velocities and amplitudes due to the presence of cracks, while upon healing both values are partially restored. To isolate the healing layer from the intact mortar around it, 3D numerical simulations are performed. A comparison between experimental and numerical results enables the determination of elastic moduli of the healing products filled in cracks. Further, a method to evaluate the stiffness and the filling ratio of healed layers at the crack is proposed, based on characteristics of elastic waves (wave velocity and amplitude).