If the pore network of a material needs to be filled with water, the sample is vacuum saturated. First the sample is oven-dried, so the dry weight of the sample and the amount of water in the pores can be determined. The sample is placed in the vacuum chamber, and the vacuum is used to remove the air in the pore network. Finally, water is added into the chamber until the sample is covered. The sample is kept immersed in water until the pores are filled.