Hysteretic moisture behavior of concrete: Modeling and analysis

Durability of reinforced concrete is crucial for civil and building infrastructures. Deterioration related to corrosion of the reinforcement can be caused by chloride diffusion or carbonation due to atmospheric CO2 ingress. Chlorides and CO2 transport coefficients are dependent on the saturation degree of the porous material. Thus, the durability of concrete elements submitted to cyclic atmospheric conditions could depend on the hysteretic moisture behavior of concrete. To assess this influence, an analytical model has been developed describing hysteretic moisture behavior based on the independent domain theory. This model is incorporated in a finite element code for coupled heat and mass transfer, allowing to calculate the concrete response to changing temperature and relative humidity conditions. A comparison is made between simulations using the hysteresis model and using either the main ad- or desorption curve. The results show that durability risks may be underestimated when omitting moisture hysteresis in the outer concrete layer.