Assessment of the Influence of Environmental Conditions on the Corrosion Rate of Reinforcing Bars in Concrete Made with Two Different Cements

In recent years, low-carbon concretes have undergone intensive development in response to the need to reduce CO2 emissions, particularly in the construction sector. One of the approaches to reducing the carbon footprint is the use of blended cements, including blast furnace cement CEM III containing a significant proportion of ground granulated blast furnace slag and composite cement CEM V. The aim of the study was to evaluate the effect of CEM III and composite cement CEM V on reinforcement corrosion and selected properties of structural concrete. Two concrete mixtures differing only in cement type were prepared. The experimental program included the evaluation of reinforcement corrosion activity using the Galvanostatic Pulse Method (GPM) on reinforced concrete specimens exposed to different environmental conditions. Additional tests included compressive strength, modulus of elasticity, shrinkage, freeze–thaw resistance, and water absorption. Based on the results obtained, it was concluded that, under the investigated conditions, namely exposure of reinforced concrete specimens to chloride ions and freeze–thaw cycles, CEM V cement may constitute an alternative to CEM III cement. This is particularly relevant because the potential environmental benefits associated with the lower CO2 emissions of concretes containing CEM V cement are supported by the available literature. Nevertheless, to verify this assumption, more detailed studies on the durability of reinforced concrete structures are required.