Influence of Loading-Induced Cracks on the Service Life and CO₂ Balance of RC Members Throughout Their Life Cycle

In the present paper, influence of loading-induced cracks on the service life and CO₂ footprint of reinforced concrete (RC) members throughout their entire life cycle, encompassing both service and post-demolition phases, is investigated. The study used 055OPC concrete (ordinary Portland cement concrete with a water-to-binder ratio of 0.55) to fabricate cubes and four beam test specimens measuring 100 mm × 120 mm × 900 mm. The beam specimens were subjected to pre-exposure loads at levels ranging from 47 to 84% of the predicted yield load, resulting in maximum crack widths of 0.1–0.32 mm for the beam segments without stirrups and 0.26–0.44 mm for those with stirrups. Then, carbonation depths at the locations of load-induced visible cracks were examined basing on the experimental results analysis. The previously proposed model was then used to predict carbonation depths in concrete containing load-induced microcracks. This analysis revealed a maximum increase of approximately 47% in carbonation depth for cracked concrete compared to uncracked counterpart. Considering the concrete carbonation depths at the locations of load-induced visible cracks and concrete with load-induced microcracks, corrosion initiation and propagation models were subsequently applied to predict the service life of the cracked RC beams and determine the optimal repair intervals. Among the cracked 055OPC RC beams, the shortest predicted service life and earliest required repair were observed for the beam with a maximum crack width of 0.32 mm and the longest crack extending 88 mm along the lateral surface, resulting in a predicted service life of 28 years. The presence of load-induced visible cracks in the concrete required at least one repair for all RC beams in their 50-year service life. Finally, an assessment of CO₂ emissions and uptake across the entire life cycle of the cracked RC beams was performed. The CO₂ balance of the beam with a maximum crack width of 0.32 mm was found to be slightly higher, showing a minor increase of 1.5% throughout the entire life cycle.