PSI - Issue 84

Martina Giglio et al. / Procedia Structural Integrity 84 (2026) 9–16 M. Giglio et al. / Structural Integrity Procedia 00 (2026) 000–000

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(2007). On the other hands, most conventional NDTs are typically discontinuous, requiring repeated site visits and window openings, providing only localized measurements, and challenging. To address the limitations of conventional NDTs, in recent years there have been growing interest in the development of non-conventional, cost-effective, and remote monitoring systems capable of providing long-term, in situ information with no interventions by Wright et al. (2019). Emerging approaches, such as wireless sensor networks and fiber-optic sensors, allow for the continuous monitoring of environmental and structural parameters, including temperature, humidity, and electrochemical conditions, that influence corrosion processes. Among these, passive wireless sensors have gained particular attention for their ability to operate without local power sources, thereby eliminating the need for batteries and wiring by Zhang et al. (2022). This feature significantly enhances stability, and accessibility in harsh or hard to reach environments by Meng and Li (2016) and by Zhang et al. (2017). In this context, Radio Frequency Identification (RFID) based sensors represent a particularly promising solution by Bouzaffour et al. (2021) and by El Masri et al. (2020). These low-cost, battery-free devices operate by harvesting energy from the electromagnetic field emitted by an external reader. Specifically, Received Signal Strength (RSSI) parameter, expressed in dB, provides critical data on the attenuation of the reflected electromagnetic wave by He et al. (2015), which can be directly correlated with the degradation process occurring in the material under investigation. Early experimental studies have already demonstrated the feasibility of passive UHF RFID tags for corrosion sensing, showing a measurable correlation between corrosion-induced material degradation and variations in the electromagnetic response of the sensing element by Virtanen et al. (2011). This method was recently applied to the monitoring of steel’s tendons in prestressed bridges by Gaillet et al. (2025). The present study investigates the use of passive RFID sensors as innovative tool for monitoring the corrosion process of metallic materials exposed to aggressive environments. By correlating the variation of RSSI signal with the progressive degradation of a sensing metallic layer, this research provide preliminary evidence of how electromagnetic signal attenuation can serve as an indirect, non-destructive indicator of corrosion activity. The outcomes of this research are expected to contribute to the broader effort of implementing smart monitoring strategies for structural health management and durability improvement of civil infrastructures. 2. RFID-based monitoring technology RFID technology is a promising solution for addressing the limitation of NDTs because these sensors operate entirely passively. They consist of a microchip and an antenna, requiring no internal power source. The necessary energy and communication are supplied remotely by a reader via electromagnetic coupling. This chapter details the operational principles of passive RFID technology as it applies to corrosion sensing. Section 2.1 will describe the specific sensor architecture and the electromagnetic mechanisms governing signal transmission. Section 2.2 will explain the Received Signal Strength Indicator, which serves as the core sensing parameter. 2.1. Theoretical principles and operating mechanism Radio Frequency Identification (RFID) is a contactless communication technology that enables the transfer of data between a reader and a tag using electromagnetic waves. A typical RFID system consists of three main components: the reader, which generates and transmits the electromagnetic field; the antenna, which mediates the coupling between

Fig. 1. RFID sensor scheme.