Non-Destructive Monitoring of Cement Hydration and Damage Using Embedded Radio-Frequency Resonance Sensors
2nd Concrete Conference (2ο Συνέδριο Σκυροδέματος), Pafos, Kıbrıs (Gkry), 28 - 29 Kasım 2025, ss.3, (Özet Bildiri)
- Yayın Türü: Bildiri / Özet Bildiri
- Basıldığı Şehir: Pafos
- Basıldığı Ülke: Kıbrıs (Gkry)
- Sayfa Sayıları: ss.3
- Orta Doğu Teknik Üniversitesi Kuzey Kıbrıs Kampüsü Adresli: Evet
Özet
The reliability of non-destructive tracking methods for hydration phases and damage assessment in cementitious materials has been previously constrained by the reliance on pointwise probes and intermittent testing approaches. This study presents an innovative compact radio-frequency (RF) resonant sensor, engineered explicitly as a printed metamaterial resonator, which is embedded within mortar cast into standard concrete cube dimensions. This configuration facilitates continuous monitoring of the material's electromagnetic signature from the moment of casting until failure. The sensor was evaluated through swept-frequency measurements to ascertain the resonant frequency (fo) and quality factor (Q). Continuous measurements were conducted at three pivotal stages: (i) immediately following casting until demoulding, (ii) during a seven-day water curing period, and (iii) throughout the compression test until failure. The results indicated a rapid increase in fo during the early phases of hydration, accompanied by a corresponding rise in Q, which aligns with the decrease in free water and dielectric loss. An immersion event caused a temporary reduction in Q; however, this value subsequently recovered as hydration progressed. During the compression tests, the onset of microcracking was signalled by an accelerated drift in fo and a notable decline in Q preceding the peak load, thereby suggesting that RF-based monitoring is capable of effectively detecting initial damage. Key early-age indicators exhibited strong and consistent correlations with the 7-day compressive strength, underscoring the potential for calibration-based strength predictions. In conclusion, the findings demonstrate that a single embedded RF resonator can deliver continuous, non-destructive indicators of curing, moisture loss, and damage evolution in mortar and concrete elements. This methodology is cost-effective, compatible with contactless readout systems, and can be readily adapted for larger structural components and durability assessments.