Study on simultaneous heat and mass tranfer in concrete at elevated temperature

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In this study, experiments and analysis were carried out to investigate the phenomena of simultaneous heat conduction and moisture diffusion in concrete at elevated temperatures.Material properties of concrete for these phenomena were studied experimentally. Furthermore, analytical studies were carried out to describe the drying process of heated concrete at elevated temperature.As the results of the experimental studies, influence of moisture content and temperature on these material properties were estimated. Especially, it was shown that heat conduction, specific heat, and specific gravity of concrete are mainly affected by moisture condition, and that the sorption isotherm and moisture conduction are significantly influenced not only by relative humidity but also by temperature.Diffusion coefficient was discussed by using the results of the sorption isotherm and moisture conduction. The diffusion coefficient of cementitious material is influenced by temperatures, and it's tendency at temperature 70 degree C is remarkably different from at 20 degree C.Simultaneous heat and mass transfer process in concrete can be simulated by separating the phenomenon into two processes and by means of finite element method.