Chloride-Induced Corrosion in Post-Tensioned Concrete Beams with Poor Grouting Condition

Chloride-Induced Corrosion in Post-Tensioned Concrete Beams with Poor Grouting Condition

Abstract

Post-tensioned prestressed concrete (PC) bridges properly designed and constructed generally have been considered highly durable because the prestressing tendons could be protected from corrosion by filling the duct with cement grout. In recent years, however, deterioration problems have been discovered in some existing PC bridges, raising serious concerns about the long-term durability of PC bridges. The major cause of deterioration in PC bridges is the corrosion of prestressing tendons, which affects structural performance in terms of serviceability and load-carrying capacity. In Japan, the major factor causing deterioration of PC bridges is chloride attack followed by poor grouting condition. The objectives of this study are to clarify the effect of grouting condition on corrosion of sheath and prestressing tendon and their influence on the deterioration of the load-carrying capacity of PC beams. To simulate deterioration of PC beams in a short period, an accelerated corrosion testing method (ACTM) was adopted. A series of accelerated corrosion tests were carried out in this study to clarify the influence of grouted ratios in a sheath on the corrosion of the sheath and the prestressing tendon. After the accelerated corrosion tests, the mechanical behaviour of the deteriorated PC beams was investigated under flexural loading.