Combined effect of corrosion and defectiveness on the bond behavior of post-tensioned prestressing steel strands

The issue of corrosion in post-tensioned bridges is gaining attention due to the progressive ageing of the existing infrastructural heritage. Especially in older structures, problems in grout injection led to the formation of voids that facilitate corrosion of the strands. Corrosion can lead to a modification of the interaction between the strand and the surrounding grout. The present work describes an experi-mental campaign on the bond interaction between strands and injection grout using pull-out tests on specimens that replicate the actual contact between the two materials. Strands had been analyzed in both corroded and uncorroded conditions, in combination with the presence or absence of a 25% defect in the grout injection.