Smart monitoring of nano-engineered concrete via piezoelectric sensors and EMI technique

Concrete structures are highly vulnerable to deterioration in aggressive chemical environments, highlighting the necessity of implementing effective durability strategies to ensure their long-term safety and performance. This paper utilises an embedded piezoelectric sensor (EPS) using electro-mechanical impedance (EMI) technique to monitor the strength growth of concrete and corrosion deterioration in reinforced concrete enhanced with graphene oxide (GO) nanomaterial. Graphene oxide concrete composites (GOCC) samples were initially prepared with varying GO concentrations to identify the optimum percentages of compressive strength of GOCC. The experiments included destructive testing for compressive strength and continuous EMI monitoring during curing to assess strength. The EMI technique also detected mechanical changes by observing shifts in conductance, peak frequency, root mean square deviation (RMSD) and equivalent stiffness. Additionally, corrosion rate is identified using gravimetric mass loss method to validate EMI findings and quantify corrosion progression. Further, the empirical equations were developed between corrosion rate, RMSD and equivalent stiffness. Results revealed that 0.03% GO yielded the highest compressive strength enhancement and EPS effectively captured the variations in peak conductance and frequency during strength gain non-destructively. Moreover, the EPS successfully identified early-stage corrosion through measurable changes in EMI signatures while equivalent stiffness degradation correlated well with observed corrosion levels.