Impact of corrosion on bond in uncracked concrete with confined and unconfined rebar

This paper examines the variation in bond strength in corroding specimens, before surface cracks are visible. Reinforced concrete specimens containing 16 mm and 12 mm diameter bars at covers of 1, 2 and 3 times bar diameter, with and without confinement, were subjected to accelerated corrosion. Bond strength is seen to increase during the early stages of corrosion (pre external cracking) for confined bars at all covers and unconfined bars at 3 times cover. However, while 16 mm bars, 1 and 2 times cover showed similar behaviour the 12 mm bars displayed a decrease in bond once corrosion was initiated.