Hee-Jeong Kim

Cement‐based supercapacitors offer a path to sustainable, multifunctional infrastructure but typically suffer from a trade‐off between mechanical robustness and ion transport. Here, we investigate how hydration‐driven pore evolution and copper mine tailing (CMT) incorporation govern this balance in cementitious composite electrodes. Structural energy‐storage composites were prepared from Ordinary Portland Cement and industrial mining waste, utilizing the natural porosity of cement paste while converting discarded mining waste into functional fillers that enhance interfacial polarization. A two‐part investigation was conducted to optimize the pore network via water‐to‐cement (w/c) ratio and enhance storage capability via CMT dosage (0.5–10 wt%). By identifying 0.6 as the optimal w/c ratio using 5 wt% CMT and then optimizing CMT content at that ratio, we found that both 2.5 and 5 wt% CMT yield comparable 28‐day areal capacitance of 6.9 mF/cm ² , while the 5 wt% CMT composite achieved a high compressive strength of 44.9 ± 3.0 MPa. Together, these results demonstrate that tailoring the mix design offers a direct method to adjust mechanics–transport trade‐offs in cement composites, demonstrating their viability as sustainable, energy‐storing structural materials.

The cement industry is a major contributor to global CO₂ emissions, creating a need for monitoring techniques that support carbon capture strategies while assessing material performance. This study investigates the accelerated carbonation curing of cement mortar using linear and nonlinear ultrasonic sensing methods, alongside mechanical and gravimetric measurements. Mortar specimens were carbonated for 1–28 days and evaluated using ultrasonic pulse velocity (UPV), the Sideband Peak Count Index (SPC-I) for nonlinear ultrasonic response, compressive strength testing, and mass-based CO₂ uptake analysis. UPV showed sensitivity primarily to bulk material changes, with comparatively less distinction among the observed responses during carbonation curing. In contrast, the SPC-I captured distinct nonlinear responses associated with matrix evolution. Early-age carbonation (2 sequestration, with average specimen mass gains reaching 2.62%. The findings demonstrate that nonlinear ultrasonic sensing provides a sensitive, nondestructive approach for monitoring carbonation curing and linking acoustic signatures to mechanical performance and carbon uptake in cement-based materials.