Dimensional Effects in CO2 Uptake and Compressive Strength of Pervious Concrete Subjected to CO2 Curing

The size effects were experimentally investigated and the underlying mechanism was analyzed. The results reveal that, as the specimen size increases, the interconnectivity of macropores slightly decreases. This in turn constrains the diffusion of CO2 and moisture in the specimens, resulting in an increase in the discrepancy between the internal and external carbonation degrees. An increase in cement paste thickness simultaneously decreases the quantity, average size, and interconnectivity of macropores, lowering the diffusion efficacy of CO2 and moisture and exacerbating the overall heterogeneity in carbonation. Moreover, the gradual blockage of macropores leads to the emergence of localized ‘occluded zones’ with much lower carbonation degree. The reduction in aggregate size significantly alters the average diameter and connectivity of macropores. leading to notable change to overall non-uniformity. This study provides insight into improving the CO2 curing effect of pervious concrete products and developing uniform curing methods.