Carbonation Behavior of an Aged Reinforced Concrete Building in Seoul

This study assessed the carbonation-related durability of an existing reinforced concrete building in Seoul scheduled for demolition to examine the level of durability performance commonly assumed for building structures. The compressive strength of concrete core specimens was compared with the estimated compressive strength derived from the rebound hammer, showing similar overall trends despite noticeable scatter, indicating that rebound testing can serve as a supplementary indicator when interpreted with caution. Carbonation depth measurements revealed that indoor locations tended to exhibit the greatest carbonation depths, likely reflecting higher CO2 concentrations associated with occupancy and daily activities, as well as indoor ventilation and moisture conditions. For exterior walls, orientation affected carbonation progress; carbonation depths were greater on the southwest-facing wall than on the northwest-facing wall, suggesting that higher solar radiation may promote drying and facilitate CO2 diffusion, thereby accelerating carbonation. When the carbonation rate coefficients were compared under similar compressive strength conditions, the southeast-facing wall exhibited a coefficient approximately 1.1 times greater than that of the northwest-facing wall. These results indicate that carbonation cannot be explained by strength alone and highlight the importance of incorporating exposure-related factors (e.g., solar radiation, drying, rainfall, and shielding) into carbonation behavior assessment.