Coupling effect of temperature and relative humidity diffusion in concrete under ambient conditions

To accurately analyze the temperature and relative humidity (RH) distribution in concrete structures under ambient conditions, based on Krstulovic-Dabic hydration kinetics, an improved hydration model is proposed to geometrically bridge the relationship between hydration degree and microstructure of cementitious materials. Both the water content and hydration heat can be individually extracted from the model to evaluate the influence of ambient conditions variation. And the adsorption curve of concrete is acquired based on the microstructure obtained from hydration model and a redistribution of moisture content in pores is applied to evaluate the hydration process accordingly. Thus, the coupling effect of RH and temperature diffusion in concrete is decoupled in terms of hydration degree. An engineering verification indicates that the model can accurately predict the development of relative and temperature in concrete structures, and the construction procedure has significant influence on moisture and heat diffusion in concrete under ambient conditions.