Carbonation and Compressive Strength Properties of Electric Power Utility Tunnel Concrete Exposed to a Carbon Dioxide Environment

Recently, the service lives of electric power utility tunnels have been increasing rapidly; however, inspection and maintenance tasks are difficult, and the economic loss owing to the end of tunnels’ lifespans is substantial. Moreover, electric power utility tunnels are exposed to high carbon dioxide. Because their interiors are sealed environments, the tunnels are significantly affected by carbon dioxide. Carbon dioxide can cause concrete carbonation, which can lead to a decline in the performance of electric power utility tunnels. In this study, the carbonation characteristics of concrete were analyzed, and the effect of carbonation on the mechanical performance was evaluated.