Superabsorbent polymers to promote and stimulate autogenous healing in cementitious materials

Concrete cracking is in some cases inevitable. Autogenous healing may prove to be useful to limit repair works caused by concrete cracking. Further cement hydration, pozzolanic activity by fly ash and calcium carbonate crystallization will hereby heal the cracks if crack widths are limited, and if sufficient building blocks and water are present. Synthetic microfibres may be used to limit the crack width, leading to strainhardening cementitious materials. The water can be provided by the use of superabsorbent polymers, which are extracting moisture from the environment. This moisture can be used for autogenous healing and may lead to a regain in mechanical properties. As the crack seems to be completely visually closed at the surface, one may ask whether this healing also is present in the interior of the crack. Thin section analysis was therefore used to study the extent of autogenous healing perpendicular to the surface, through a crack. The autogenous healing in a cementitious material is dependent on the crack depth. Only the first part of the crack is closed by crystal formation in case of wet/dry cycles. In combination with superabsorbent polymers, the extent of healing was more substantial, even in the interior of the crack. The smart cementitious material with superabsorbent polymers thus is an excellent material to use in future building applications