Measurement of Diffusion Coefficients in Building Materials Using the Initial Rate of Sorption

This work presents experimental values of molecular diffusion coefficient, obtained with samples of building materials, using a non-stationary process of moisture absorption. The experiments covered four different types of building materials (with two selected ranges of relative humidity) and were carried out in the range of temperatures between 20ºC and 40ºC. The results show that the increase in temperature resulted in an increase in molecular diffusion coefficient and the relative humidity also influenced the molecular diffusion in a uniform manner. Finally, a good agreement with literature values was found.