Corrosion of ribbed carbon steels in ecological mortars and its influence on their rotative fatigue behavior

Ribbed carbon steel rebars were embedded in mortars manufactured with three different eco-friendly binders (alkali-activated slag, and slag and fly ash-based hybrid cements) and with a commercial cement (CEM IV). This research evaluates the corrosion of reinforcements, fully assessed by natural diffusion, and its impact on the fatigue performance of the bars. Results obtained after 17-month corrosion testing on reinforced innovative mortars reveal that different pit morphologies and locations appear on the bars depending on the mortar composition, with the extent of the attack being related to the pH and the free-chloride content in each mortar. Rotative fatigue tests of the corroded bars have proven that the reduction of the fatigue life is dependent on the global extent of the corrosive attack, when the shape and distribution of the pits correspond to those generated exclusively by chloride diffusion in mortars. Bars corroded in alkali-activated slag and CEM IV mortars shown the best fatigue performances.