Influence of corrosion-based section loss on morphology and tensile capacity of pre-stressing strands

Pre-stressing steels used in pre-stressed concrete undergo degradation when exposed to a corrosive environment resulting in eroded mass. This paper presents the experimental results of tensile strength variation of prestressing strand with respect to section loss. Surface morphology, corrosion type and mode of rust deposition under the influence of accelerated corrosion were also investigated. 12.7 mm seven wire strands of 1860MPa characteristic strength were used for the study in comparison with non-corroded strand as control specimens. The variation of above-mentioned factors was initially compared on the basis of target weight loss in the range of 0.1%, 0.5% and 1%. It is observed from the accelerated corrosion that hydrogen embrittlement mechanism occurred resulting in shallow and wide eroded mass in the form of uniform corrosion occurring with increase in the corrosion rate. Results were more pronounced for 1% weight loss with 36% drop in tensile strength. The paper concludes that accelerated corrosion is a widely chosen procedure by researchers to validate the study on corrosion as it can be achieved in a shorter time period and this method was effectively utilized in the study of relation between loss of weight due to corrosion and tensile strength.