Investigating correlations between crack width, corrosion level and anchorage capacity

Artikel i vetenskaplig tidskrift, 2017

In assessing existing structures, inspection results need to be linked to the effects on load-carrying capacity; to provide such information, this study has investigated the correlation between splitting crack width, corrosion level and anchorage capacity. The study was based on 13 reinforced concrete beams that had been exposed to natural corrosion for 32 years, eleven beams with splitting cracks and two without. The crack pattern and widths were documented before undergoing structur-al testing of anchorage capacity. Thereafter, the reinforcement bars were extracted and their corro-sion levels measured using two methods, gravimetric weight loss and 3D scanning. The corrosion level from the weight loss method was approximately twice as large; possible reasons are horizon-tal or subsurface corrosion pits, and the cleaning method. Further, for the same corrosion level, the specimens in this study had much larger crack widths and slightly lower bond capacity than the artificially corroded tests in the literature; a possible reason is that these specimens had been sub-jected to combined corrosion and freezing. However, the corrosion level and reduction in bond ca-pacity related to crack width were both lower in the present than in previous studies in the litera-ture. Thus, by formulating a damage indicator from the damage visible in the form of crack widths from artificial test data, the structural capacity is estimated to be on the safe side.