Service life prediction of a concrete bridge structure subjected to carbonation

Carbonation-induced corrosion in concrete may often occur in a high carbon dioxide environment. In this study, the risk of carbonation of a concrete bridge in an urban area was evaluated by measuring the carbonation rate and concrete cover depth in three different parts: the sound, cracked and construction joint parts of cover concrete. The average carbonation rate was ordered by the sound > joint > cracked parts, and the concrete cover depth measured by an ultrasonic detector indicated the slightly greater value than the designed one (50.0 mm). Then, the carbonation-free service life at the depth of the steel was calculated, based on in situ information, by the safety factor method and the Monte Carlo simulation. The service life calculated by the two methods was mostly identical. The sensitivity of the carbonation rate and concrete cover depth to the time to carbonation at the depth of the steel was mathematically determined.