Water movement in porous building materials—XIII. Absorption into a two-layer composite

The sharp wet front method of analysis is applied to the absorption of water into a composite bar consisting of two dissimilar materials in hydraulic contact. Equations describing both the rate of absorption of water and the cumulative absorbed volume of water per unit area of supply surface are derived. Experimental absorption data can be used to estimate the ratio of the hydraulic conductivities of the constituent materials. Experimental data on composite bars made up of various plaster I sand mixtures are included for the case of absorption through a high sorptivity into a lower sorptivity material. The results show that the absorption of water into the composite is controlled by the properties of the second material.