Reusing and Recycling Superabsorbent Polymers for Sustainable Sealing and Healing in Cementitious Materials

Currently, there is a lot of focus on sustainability and circularity in the built environment to increase its durability. Some solutions, such as adding superabsorbent polymers to induce sealing and healing effects in cementitious materials, require the use of derivatives from the petroleum industry. Although these polymers are added in small amounts, they are environmentally unfriendly due to the carbon emissions associated with their fabrication. These polymers are used in the hygiene industry and often end up in waste landfills. However, they can be recycled and reused. This paper explores the use of recycled SAPs in cementitious materials and investigates whether they can achieve similar properties and characteristics, such as regaining impermeability and visual healing. The polymers are obtained by recycling diapers and hardened cement paste containing the polymers. Both virgin and recycled superabsorbent polymers showed reduced permeability compared to reference sample, with the virgin one performing slightly better than the others. The healing process was more visible in the specimens containing superabsorbent polymers compared to the reference samples, and the trends were consistent across all specimens. However, there was a minor decrease in the overall swelling properties of the recycled superabsorbent polymers. Both the commercial and recycled superabsorbent polymers yielded comparable results in terms of reduced compressive strength. The study demonstrates the potential of reusing superabsorbent polymers for more sustainable sealing and healing of cementitious materials. Future research will investigate the complete life cycle assessment associated with overall durability.