Amine-Functionalized Carbonate Mortars of CO₂ Absorption for Carbon Neutrality and Enhanced Rebar Corrosion Resistance

This study investigated the effects of carbon dioxide (CO₂) uptake by dimethylamine (DMA), diethylamine (DEA) and isopropylamine (IPA) in amine-added cement mortars and the corrosion resistance of rebars covered with amine-added mortars in the presence of 4% calcium chloride solution. Quantitative findings showed that DEA at 2% demonstrated the highest CO₂ uptake rate, which was 1.8 times faster than that of the control mortar. In corrosion tests, DMA and DEA mortars exhibited a 40–85% decrease in corrosion potential after 15 days compared to initial values, indicating improved corrosion resistance. However, in saltwater tests, all samples showed corrosion potential values below − 350 mV after 12 days, suggesting active corrosion. Qualitatively, the amines demonstrated improved corrosion resistance compared with the control samples, with DMA and DEA being more effective than IPA. This enhanced performance is attributed to the ability of amines, particularly DEA, to adsorb onto the surface of the rebar and form a protective layer, increasing the pH of the pore solution and potentially binding with chloride ions. This research presents a new model for the production of building materials using innovative technologies to reduce atmospheric carbon dioxide content while also enhancing durability. The study highlights the complex interplay between CO₂ absorption, carbonation, and corrosion processes in amine-modified cementitious materials, providing valuable insights for developing more sustainable and durable concrete structures.