Investigation of dynamic capillarity in cement and clay composites

The movement of water within building materials is one of the key factors affecting both durability and overall performance. Especially under external environmental conditions, the way and rate at which water penetrates into the material play a critical role in the development of long-term damage mechanisms. In this study, the capillary behavior of water in cement-based and clay-based composite materials was experimentally investigated under static and dynamic conditions. In static capillarity tests, water was allowed to contact only the bottom surface of the samples, and the upward movement of water in a stationary environment was observed. In the dynamic tests, water was applied at a constant flow rate under five different slope angles (0%, 3%, 5%, 7%, and 9%), and the effect of increasing slope—thus increased water velocity and reduced contact time—on capillary absorption was analyzed. The results showed a significant decrease in capillary water uptake under moving water conditions, and this effect became more pronounced with increasing slope. Furthermore, parameters such as the binder structure in the cement matrix, the use of additives, and the porosity level of the clay-based material were found to have a substantial impact on the internal water transport. This study emphasizes the need to consider not only total water absorption but also the behavioral differences in water movement under static and dynamic conditions, offering a new evaluation approach for material durability.