In situ characterisation of the depth and mass of water intrusion in unsaturated cement pastes via X-ray computed tomography

X-ray computed tomography was applied to continuously track the migration process of water in unsaturated cement pastes in situ. It was found that the process of water uptake starts with early rapid growth and a subsequent slowly increasing period, followed by a relatively stable stage. The rate of water penetration was accelerated with a decrease in slag incorporation. An analytical equation was developed to establish the relationship between the depth and the mass coefficient of capillary suction and the obtained predicted values were found to be in excellent agreement with the experimental values observed via the gravimetric method.