Concrete has a crucial role in protecting reinforcement steel from corrosion. The high alkalinity of cement promotes the formation of a passive layer on the steel, protecting it against corrosion. Destabilization of this layer can happen because of the presence…
Concrete has a crucial role in protecting reinforcement steel from corrosion. The high alkalinity of cement promotes the formation of a passive layer on the steel, protecting it against corrosion. Destabilization of this layer can happen because of the presence of chlorides, or because of a pH reduction due to carbonation of the cement matrix due to ingress of CO from the 2 atmosphere. Corroded steel reinforcement leads to a reduction of the mechanical properties and can induce accelerated fracture formation. As chloride ions are transported via liquid water, the water permeability plays an important role. Moreover as carbonation is determined by the transport of CO2 in the remaining gas phase, the gas permeability also plays a major role. The water and gas permeability are directly depending on the saturation degree or moisture content. Concrete shows a strong hysteresis in sorption, and consequently, the permeability and the ingress of e.g. chlorides and CO , - and thus the durability of concrete - will be highly influenced by the hysteretic moisture 2 behavior. In this paper, we present a sorption hysteresis model for concrete based on the independent domain theory.