Shruti Singh

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.