ABSTRACT
Capillary absorption of water is of great significance to accurately quantify their durability performance and predict their service life. However, the measured capillary absorption of water into cement-based materials will always deviate remarkably from the square root of time law sooner or later and obeys a bi-linear law, which could not be captured by conventional models. In this study, the permeability of cement-based material is assumed to be dependent on contact time. We adopt exponential as well as doubly exponential functions to describe the time-dependent permeability and then implement them into the conventional transport model. The results show the time-dependent permeability models of both forms help capture the anomalous water absorption kinetics. The calculated absorption kinetics is rather sensitive to the decay time constant τ, which still needs further research.
