Service Life Prediction of an Aged Bridge Based on Carbonation Tests of Cross-Section Cutting-Off Girders

This paper presents the details of carbonation tests conducted on cross-section cutting-off girders from a reinforced concrete (RC) bridge and proposes a method to predict the service life of an RC bridge based on the extent of deterioration associated with corrosion of the reinforcing bars due to carbonation and chloride ion attack. Service life prediction is a crucial part of systematization of bridge maintenance. Bridges are typically exposed to a range of environmental conditions over their service lives. Deterioration of RC bridges due to carbonation may occur and may have a significant effect on service life. Chloride ion attack may also influence the deterioration process if the bridge is located close to the sea. Many previous studies have examined the effect of carbonation on RC bridges. However, this paper describes the first known application of carbonation tests to cross-section cutting-off girders from a bridge. A flowchart is presented for the proposed method for predicting the service life of an RC bridge based on the extent of deterioration due to carbonation and chloride ion attack. The results show that the main factor in the deterioration of the bridge has been carbonation and that chloride ion attack has also contributed to the deterioration of the bridge. The end of the service life was defined as the point at which the cumulative amount of steel corrosion reached a critical value of Q = 75 mg/cm 2 . The service life of the bridge was predicted to be approximately 81 years (remaining life of approximately 9 years) on the sea side and mountain side and approximately 142 years (remaining life of approximately 70 years) on the bottom side. The service life for the bottom side was predicted to be longer because of repair work done on the bottom side.