Predicting depth of carbonation of concrete for varying climatic conditions

Abstract

Corrosion of reinforcing steel is the result of poor durability performance of reinforced concrete structures. Carbonation of concrete caused by the diffusion of carbon dioxide into the concrete is one of the major factors responsible for reinforcing steel corrosion. A carbonation model which predicts the rate and extent of carbonation is useful not only in the design phase by facilitating the right choice of materials, but also in helping to assess the rate and extent of carbonation of existing structures. Most of the currently available carbonation models predict the depth of carbonation based on constant humidity conditions. The influence of varying climatic conditions (i.e., drying and wetting cycles) is not taken into consideration in predicting depth of carbonation. However, current approaches may be conservative or non-conservative, depending on the different climatic conditions which influence the rate of carbonation. The main aim of this study was to develop or modify a carbonation model to as to accommodate varying climatic conditions. The carbonation model developed is validated based on experimental data from specimens prepared with different concrete mixes exposed to natural carbonation.