Abstract: Capillary water absorption in porous rock, as a water transport phenomenon, is of extreme importance in many fields. The kinetics of capillary water absorption of rock was derived and discussed in detail, and then a new approach of measuring the capillary water absorption was proposed. We conclude that 1) the new approach is based on measuring residual water, thus is simple and accurate in continuously measuring the genuine water absorption rate of rocks, and meets two-dimensional or three-dimensional boundary conditions; 2) in the initial stage of water absorption of gypsum rocks, the relationship between water absorption value and time is consistent with capillary theoretical model; 3) the relationship between correlation coefficient and frequency during the fitting of test data proves that the new approach has small errors and the test data is stable and reliable.

Key words: gypsum rocks, capillary phenomenon, rock imbibitions, test method, measurement method