Dependency of pitting corrosion spatial variability on crack pattern of prestressed concrete members

Many existing reinforced concrete (RC) and prestressed concrete (PC) bridges all over the world are affected by corrosion deterioration of reinforcements. Therefore, the assessment of the re-sidual life of corroded structures and infrastructures results strategic to plan maintenance activi-ties and to limit sudden collapses, traffic disruptions and fatalities. The lack of consolidated methods for assessing the residual capacity of corroded PC members in engineering practice is related to the limited experimental and numerical researches available in the scientific literature. Indeed, limited works investigate the uncertainties in the correlation between the damage induced by corrosion and the structural resistance. The main novelty of the present study consists in the measurement-based correlation between the pitting corrosion spatial variability in prestressing strands and the crack pattern in PC members, caused by spalling of cover or splitting cracking of concrete. To this aim, the present study investigates several prestressing strands retrieved from six 10-years-old naturally corroded PC beams subjected to chloride ions attack during their ser-vice lifetime. Firstly, the surface defects of each analysed PC beam were mapped and the corre-sponding position of each retrieved sample was reported. Secondly, 3D-models of corroded strands were developed and the GOM Inspect software was adopted to measure the penetration depth of each scanned pit. Finally, useful correlations were derived for relevant variables such as the maximum penetration depth and the number of pits per meter. In this regards, two different groups were identified consisting of strands (i) retrieved and (ii) not retrieved from zones of PC beams characterised by the presence of splitting cracking. The results show that cracking of concrete play a fundamental role in the corrosion spatial variability of prestressing strands