Life cycle environmental impact of flexural steel reinforced concrete beams under the coupled degradation of crack development and steel corrosion attack using a stochastic approach

Chloride-induced corrosion poses a serious threat to steel-reinforced concrete (RC) elements, increasing life cycle environmental impacts (LCEI) through frequent maintenance and replacement. This study develops a stochastic framework that integrates reliability analysis with life cycle assessment to quantify the LCEI of flexural RC beams under coupled degradation resulting from steel corrosion and the development of mechanically induced cracks. Results demonstrate that neglecting this coupled degradation significantly underestimates LCEI. This study shows that higher traffic loads accelerate deterioration and increase environmental impacts, whereas supplementary cementitious materials (SCMs) reduce LCEI in proportion to their ability to bind penetrating chlorides. Furthermore, combining SCMs with hydrophobic surface treatments delays chloride ingress and reinforcement corrosion, yielding additional LCEI savings. Finally, this study assesses the effect of safety margins on LCEI, offering guidance for design optimization based on structural criticality. This framework provides a robust tool for enhancing the sustainability and performance of RC flexural elements.