Understanding intrinsic healing process in cementitious cracks through modeling and experiments

This study aims to understand the intrinsic healing process along crack depth in cementitious materials with various physical and chemical parameters. A new, coupled transport-thermodynamics model was formulated to predict crack wall profile change with time due to healing. The model considers the time-dependent interaction among ions transport through crack depth, healing products precipitation along crack walls, and local alteration of crack transport properties. The model was validated by controlled experiments quantifying the 3D crack aperture field before and after healing. Using X-ray computed microtomography, scanning electron microscopy and chemical analysis, the experiments uncovered and quantified the non-homogenous healing ratios and chemical compositions along crack depth. Parametric studies further elucidated how different physical (crack width, geometry, flow rate) or chemical (unhydrated cement ratio, ion concentration) parameters affect the healing profile change with time. The results shed light on the intrinsic healing mechanisms and robustness in cementitious materials.