Real-time monitoring of residual strength in corroding steel reinforcement using ultrasonic-guided waves and multi-physics modelling

Abstract

Corrosion-induced material strength degradation is a major threat to the service life of reinforced concrete (RC) structures. Continued mass loss and pit formation after the initiation of corrosion in reinforcing steel consequently results in strength degradation. In this study, a non-destructive structural health monitoring (SHM) approach using ultrasonic guided waves with multi-physics modelling to monitor and forecast strength degradation of corroding steel is presented. Surface-bonded piezoelectric wafer transducers (PWTs) are used for actuating and sensing of guided waves in order to correlate the group velocity and amplitude of flexural wave modes with the strength reduction. The major findings of the work are presented in the form of empirical relationships between guided wave characteristics with reduced yield, ultimate, and buckling strength of corroded steel. It is observed that for a rebar of 12 mm diameter having slenderness ratio between 8 and 10, a 10% increase in amplitude and 8.44% increase in group velocity of flexural mode for corroding steel indicates a corresponding reduction of 10.278% in yield strength, 10.277% in ultimate strength, and 4.45% in buckling strength in progression phase of corrosion. A multi-physics numerical model of corrosion in RC structures that considers the effect of local exposure and environment is then elucidated with deviation less than 6.34% from experimental results in order to forecast the mass loss. The presented data fusion strategy, which combines guided wave-based monitoring and multi-physics modelling finds valuable application in assessing the current state of degradation in structural performance and strength-based service life prediction.

Keywords:

• Ultrasonic guided waves
• residual strength
• corrosion in steel
• NDT
• SHM
• sensor

Acknowledgements

Authors acknowledge the opportunity for presenting part of the contents presented in this manuscript in 2nd International Conference on Corrosion and Surface Protection for Steel (CASP 2022), Organised by the Turkish Constructional Steelwork Association (TUCSA), Turkey, Istanbul, in coordination with the European Convention for Constructional Steelwork (ECCS). Authors acknowledge the computational facility provided by CCES, IIT Bombay. The authors acknowledge the support from NMAM Institute of Technology, Nitte during the course of this research work. Authors would like to thank Prof. R K Singh and Dr. Rajeshwara Chary Sriramadasu at IIT Bombay for their suggestions during the course of this research work.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.

Author’s contributions

Shanmukha Shetty: Conceptualisation, Data curation, Formal analysis, Investigation, Methodology, Software, Validation, Visualisation, Writing – original draft. Sauvik Banerjee: Conceptualisation, Methodology, Investigation, Resources, Funding acquisition, Supervision, Writing – Original Draft, Writing – Review and Editing. Siddharth Tallur: Conceptualisation, Methodology, Investigation, Resources, Funding acquisition, Supervision, Writing – Original Draft, Writing – Review and Editing. Yogesh M Desai: Conceptualisation, Methodology, Investigation, Resources, Supervision, Writing – Original Draft, Writing – Review and Editing.

Availability of data and material

The authors confirm that the data supporting the findings of this study are available within the article.

Additional information

Funding

The authors acknowledge the support of IMPRINT-2A by Science and Engineering Research Board, Department of Science and Technology, Government of India [grant IMP/2018/001442] for the development of experimental facilities.