Deterioration of prestressed concrete beams due to combined effects of carbonation and chloride attack

Performance of prestressed concrete (PC) beams subjected to both carbonation and chloride ingress has not been clarified well so far. This paper presents the evaluation results and discussion on materials deterioration and corrosion state of prestressing wire/tendons of 35 year's test PC beams. All beams were exposed to the actual marine tidal environments at the Sakata Port more than 20 years, then transferred and stored in a constant temperature over 15 years. The results indicated that all beams showed deterioration on the exterior and the whole surface of beams was carbonated. Even carbonation did not cause corrosion of reinforcement, however, it may have contributed to degradation of cover concrete. In addition, even though tendons were protected by sheath and mortar grouting, however, corrosion area on tendons reached 40%, and prestressing wires corrosion length was 50 to 73%, indicating severe corrosion conditions for PC beams with 30 mm cover depth.