Experimental determination of the water vapor diffusion coefficient of autoclaved aerated concrete (AAC) via a transient method: Effects of the porosity and temperature

摘要

In this Short Communication, the water vapor diffusion coefficient of autoclaved aerated concrete (AAC) samples with various apparent densities was measured using a transient method that is based upon solving an inverse problem of one-dimensional water vapor diffusion. The transient measurements were performed over a relative humidity (RH) range from 1% to 90% at temperatures between 15 ℃ and 45 ℃. It was revealed that the dependence of water vapor diffusion coefficient on the presence of pores cannot be simply correlated to either apparent porosity or open porosity. The pore structure, as quantified by pore size distribution, was found to be responsible for the relative comparison among the various AAC samples. It was also exhibited that the water vapor diffusion coefficient is enhanced at higher temperatures, whereas its RH-dependence is significantly suppressed at lower temperatures.