Carbonation of concrete in the tropical environment of Singapore

Abstract

The experimental investigation was performed to study the influence of unit cement content and w/c ratio on the rate of carbonation under natural exposure in the tropical environment of Singapore together with laboratory accelerated carbonation test. To represent concrete of lean to rich mixes, the cement content in a total of 21 mixtures was varied from 250 to 450 kg/m3, while the w/c ratios ranged between 0.40 and 0.70 with an increment of 0.05. After 14 years of natural exposure, the 28-day compressive strength (f 28) and w/c ratio (w/c) were identified as reliable parameters for estimating the depth of carbonation. However, within the range of values studied, there is no significant effect of the cement content on the carbonation behaviour. The relationship between the 14-year natural exposure and the samples from the 7% CO2 concentration accelerated test were also correlated. Tentative recommendations on the use of the findings in durability design against carbonation for required service life in a t...