In-situ polymerized superabsorbent polymers for durable cementitious materials

When a cementitious material is hardening, it may show shrinkage cracking. The ingress of water containing potentially harmful substances through these cracks could endanger the durability of a structure. The goal of this project is to enhance the overall durability by limiting the observed shrinkage cracking and to seal the remaining cracks in existing structures by using superabsorbent polymers (SAPs), materials which are able to absorb huge amounts of liquids. The subject of this project is a new and innovative technique of polymerizing these SAPs in situ, meaning during hardening of the cementitious material or on a cementitious substrate both in fresh and hardened state. This project aims to investigate proper in-situ polymerizable SAPs, to mitigate plastic shrinkage of fresh concrete and/or to seal cracks in existing structures by using an external in-situ polymerized SAP layer. Additionally, the SAPs will be in-situ polymerized during mixing of all cementitious constituents to induce internal curing and thus to mitigate autogenous shrinkage. High-tech techniques (e.g. NMR) will be used to monitor the polymerization and to investigate the influence on various cementitious properties. The research will shed more light on the fundamental interactions between water, SAPs and cementitious materials.