Dual-setting mineral cements: Synthesis, novel reinforcement mechanisms, and application in additive manufacturing techniques

• Applicants: Professor Dr. Uwe Gbureck; Professor Dr. Jürgen Groll
• Subject Area: Glass, Ceramics and Derived Composites ; Biomaterials
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 577498932

The project focuses on the development and investigation of dual-setting mineral cements, in which the simultaneous formation of an interpenetrating hydrogel phase from natural or synthetic precursors enables the adjustment of a pseudo-ductile fracture behavior. The stimulus for gelation can be extrinsic, for example by the addition of a suitable initiator system, or intrinsic in nature, such as through the reaction conditions of the cement hydration process (pH value, ion release, water). In the further course of the project, a detailed investigation of the underlying reinforcement mechanisms (self-compaction and intrinsic prestressing) will be carried out using silk fibroin-modified cements as a model system. These mechanisms will subsequently be replicated using synthetic polymers. Another approach addresses dual-setting cements with a purely inorganic (silica) matrix, which will be transferred to technical cement formulations and further optimized through targeted precursor synthesis. In particular, branched silica precursors will be specifically synthesized to increase the degree of crosslinking. These precursors will be functionalized with carboxylate groups for binding divalent cations (e.g., Ca²⁺ or Mg²⁺), in order to achieve improved chemical interaction with the cement matrix. Furthermore, technical cements based on calcium aluminate will be modified with isocyanate-containing prepolymers. According to previous experience, the advantages here include easy processability, since the mixing water of the cement itself induces gelation without further additives, combined with excellent fracture-mechanical properties. Finally, the project will explore how these material systems can be adapted to additive manufacturing processes such as extrusion-based direct ink writing, 3D powder printing, or photochemically crosslinking techniques by tailoring specific material properties. The knowledge gained from material development is not limited to the biomaterials field but also explicitly addresses technical applications, such as additive manufacturing in construction.

• DFG Programme: Research Grants