Capillary rise in granitic rocks: Interpretation of kinetics on the basis of pore structure

The capillary transport of water into granitic rocks has been interpreted o n the basis of the structure of its porous network. An effective pore radiu s has been calculated from a three-sized single-pore model proposed by F. A . L. Dullien, El-Sayed, and V. K. Batra (J. Colloid Interface Sci. 60, 497, 1977) Considering the porous network of granites as consisting of fissures grouped in two size types, macro- and microfissures, an effective radius w as found from the characteristic radii for each type and the average of the se two values. Good agreement between the effective radius calculated and t he radius estimated using a capillary rate value measured experimentally pr ovides a suitable basis for identifying interrelationships between the pore structure and moisture capillary rise. In fact, it is possible to predict the process rate from only two characteristic pore sizes! corresponding to the radii of macrofissures and microfissures. The abnormally low rate of ca pillary rise observed in one of the granites studied could be easily interp reted as due to the involvement exclusively of the macrofissures of its por ous network in capillary transport. (C) 2000 Academic Press.