Effect of Graphene Oxide on the Physical and Mechanical Properties of Concrete Composite during Initial Hydration and Strength Growth Using an Electromechanical Impedance Technique

Nondestructive monitoring of concrete composite strength growth is of great importance for the safety and stability of engineering structures. Traditional destructive testing methods are limited in providing real-time assessment. This study proposed a novel method to investigate the effect of graphene oxide (GO) on mechanical properties, resonance frequency, amplitude, statistical parameters, and equivalent stiffness of concrete composites during the initial hydration (IH) and strength growth. An electromechanical impedance (EMI) technique using an embedded piezo sensor (EPS) was employed to monitor initial hydration and strength growth of GO concrete composite (GOCC) specimens. GO was added at 0.03% by weight of cement. The experiments involved recording both the compressive strength (measured destructively) and EMI response throughout the curing process. Statistical indices were calculated to quantify changes during IH and strength growth. The equivalent stiffness parameter was extracted from the EMI raw signatures to assess stiffness gain over time. The addition of GO (0.03% by weight of cement) resulted in a 31% increase in compressive strength at 3 days and a 25% increase at 28 days compared with conventional concrete (CC). The EPS effectively captured variations in resonance peak and conductance amplitude during the IH and strength growth. The trend of equivalent stiffness values closely matched the growth in compressive strength. A strong correlation was found between equivalent stiffness and compressive strength, with a coefficient of determination (R2) of 0.975. The results demonstrate that the proposed nondestructive method offers significant advantages in terms of reliability, quantitative precision, robustness, and real-time capability. The study concludes that the use of GO enhances the mechanical properties of concrete composites, and the EPS-EMI method can effectively monitor strength growth and hydration in real-time, providing a viable tool for structural health monitoring.