Autogenous healing of cementitious materials promoted by superabsorbent polymers studied by means of X-ray computed microtomography D. Snoeck 1,2 , J. Dewanckele 3 , M. Dierick 4 , L. Van Hoorebeke 4 , V. Cnudde 3 , P. Dubruel 2 and N. De Belie 1 1 Magnel Laboratory for Concrete Research, Department of Structural Engineering, Faculty of Civil Engineering and Architecture, Ghent University, Technologiepark-Zwijnaarde 904, 9052 Ghent, Belgium – e-mail: Didier.Snoeck@UGent.be, Nele.DeBelie@UGent.be 2 Polymer Chemistry and Biomaterials Group, Department of Organic Chemistry, Faculty of Sciences, Ghent University, Krijgslaan 281 S4bis, 9000 Ghent, Belgium – e-mail: Didier.Snoeck@UGent.be, Peter.Dubruel@UGent.be 3 Centre for X-ray Tomography/PProGRess, Department of Geology and Soil Science, Faculty of Sciences, Ghent University, Krijgslaan 281 S8, B-9000 Ghent, Belgium – e-mail: Jan.Dewanckele@UGent.be, Veerle.Cnudde@UGent.be 4 Centre for X-ray Tomography, Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Proeftuinstraat 86, B-9000 Ghent, Belgium – e-mail: Manuel.Dierick@UGent.be, Luc.VanHoorebeke@UGent.be Keywords: self-healing, self-sealing, hydrogels, µCT Autogenous healing of cracks may offer a solution for brittle cementitious materials. Further cement hydration and calcium carbonate crystallization will hereby heal the cracks if sufficient building blocks and water are present. The building blocks are available through the well-designed mixture with a low water-to-binder ratio and water is available through the inclusion of superabsorbent polymers. These polymers are able to extract moisture and fluids from the environment and to provide it to the cementitious matrix for autogenous healing. This healing will lead to the regain in mechanical properties, as already found in previous research. As the crack seems to be completely visually closed at the surface, one may ask whether this healing is also present in the interior of the crack. X-ray computed microtomography was therefore used to study the extent of autogenous healing in cracked cylindrical specimens after autogenous healing. It was found that 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. There was even partial healing in the interior of the crack when stored at a relative humidity of 60% or more than 90%, but only in mixtures containing superabsorbent polymers. The smart cementitious material with superabsorbent polymers thus is an excellent material to use in future building applications as the healing extent is improved.