Quantitative moisture model of interior concrete in structures exposed to natural weather

The moisture in interior concrete is the primary factor directly influencing the deterioration phenomena of concrete structures. In this study, a method for predicting the moisture of the natural environment and the interior concrete was proposed based on the relative humidity (RH) and water vapor density (WVD) concepts using meteorological data. The variations of the moisture in the environment and the interior concrete were measured and modeled. After experimental validation, the moisture model was extended to investigate the action spectrum of humidity in the environment and the reaction spectrum of moisture in the interior concrete based on monthly and annual meteorological data. The results show that the characteristics of the RH and WVD differ from one another in both the environment and the interior concrete as a result of the intrinsic properties of the concrete. In the atmosphere, the RH fluctuates periodically with the diurnal cycle, whereas the WVD shows only slight fluctuations. In the interior concrete, the WVD fluctuates periodically, whereas the RH is relatively steady and tends towards a constant beyond a critical depth. Thus, it is proposed that the WVD, supported by the RH, be used to quantitatively characterize the moisture and the RH be used to qualitatively characterize the moisture.