Corrosion cracking: Image-based methods combined with modelling

Research Project, 2020 – 2022

Are ageing civil engineering structures safe to use? This question urgently need an answer. We will enable assessment of the safety of deteriorated reinforced concrete structures based on visual inspection, by linking cracking with structural safety. Commonly, one deterioration mechanism at a time has been studied; however, recent results show strong interaction between corrosion, the major cause of deterioration, and freezing. Further, almost all research is based on artificially corroded specimens; there are major concerns whether natural corrosion affects the structure differently. Finally, reinforcement corrosion causes concrete cracking; this involves several phenomena, which currently cannot be separated. In this project, neutron tomography will give an insight into the structure during the corrosion process, thus providing the required data for both artificially and naturally deteriorated samples. Nonlinear finite element analyses will be used, describing volume expansion, granular behaviour of rust, porous zone, transport of rust through cracks, non-uniform corrosion, and frost. Thus, the phenomena will be separated and their combined action understood. Ultimately, the project will contribute to significant economic and environmental savings for society, and to the preservation of cultural heritage structures, as the improved knowledge will allow us to repair and replace existing structures only when necessary, still guaranteeing the required structural safety.