Influence of carbonation on torrent air permeability of concrete

Abstract

Air permeability testing is increasingly being used to measure the impermeability of concrete and to estimate the durability of reinforced concrete structures using this property. This paper presents the results of a preliminary study on the influence of the carbonation of concrete on its air permeability measured using the Torrent apparatus. Three batches of concrete made with CEM I cement and differing in the w/c ratio (0.45, 0.50, and 0.55) were tested. The influence of the relative humidity of concrete on the air permeability index kT was assessed using relationships available in the literature. It was shown that in carbonated concrete, these relationships need to be modified. The air permeability values obtained in tests are lower than the theoretical values calculated using the equation. The results obtained suggest that the effect of carbonation on the air permeability of concrete is significant and further research in this area is highly recommended.