Non-Destructive Strength Monitoring of Air-Entrained Concrete via Electromechanical Impedance Technology

Accurate monitoring of concrete strength during curing is crucial, particularly in regions subject to harsh weather conditions, such as freeze-thaw cycles in Indiana. Air entrainment is crucial for durability, yet it can significantly reduce concrete strength, making timely and precise strength assessments vital. The primary objective of this study is to develop a non-destructive and real-time monitoring framework for evaluating mortar strength using electromechanical impedance (EMI) sensors and ultrasonic scanning technology. This research holds significant value as it addresses the critical need for continuous, reliable concrete strength monitoring, potentially reducing reliance on destructive testing methods, which are costly and time-consuming. The study employed piezoelectric (PZT) sensors embedded within mortar cubes, continuously capturing EMI signals. Concurrently, ultrasonic scanning provided key data on phase velocity and attenuation coefficients throughout the curing period. These non-destructive methods were validated through periodic destructive compressive strength testing of five mortar cube groups, each varying in air content through traditional and innovative air-entraining agents. Results indicated a strong positive correlation between ultrasonic phase velocity and compressive strength (r=0.946), and a strong negative correlation for the attenuation coefficient (r=-0.890). EMI-based Root-Mean-Square Deviation (RMSD) analysis yielded regression values between 0.761 and 0.992, demonstrating its reliability in strength prediction across varying conditions. The implications of this study suggest that integrating EMI and ultrasound techniques provides an effective real-time solution for strength monitoring, significantly enhancing decision-making and predictive accuracy in concrete infrastructure projects.