Frau Jiříčková und Frau Lauermannová sind assoziierte Mitglieder des Graduiertenkollegs GRK 2802 und wurden am Institut für Anorganische Chemie der Universität für Chemie und Technologie (VŠCHT)  in Prag von Prof. Ing. Ondřej Jankovský, Ph.D. betreut. Ihre Dissertationen setzen sich mit der Entwicklung von modernen Bauverbundwerksfoffen auf der Basis von Sorel-Zement auseinander. Die Motivation beider Dissertationen war die Senkung des CO₂-Fußabdrucks von Konstruktionsbaustoffen, indem anstatt Portlandzement Sorel-Zement verwendet wird. Die schlechte Wasserbeständigkeit von Sorel-Zement basierten Baustoffen wurde durch Zugabe von speziellen hydrophoben Additiven, u.a. Graphenoxide, CNT und Kohlenstoffkugeln hergestellt aus recyceltem Plastik, (Adéla Jiříčková) sowie Tanninsäure, MoS₂ und Al₂O₃ Nanosheets (Anna-Marie Lauermannová), signifikant verbessert. Darüber hinaus wurde von Anna-Marie Lauermannová Abfallmaterial aus der keramischen und feuerfesten Industrie (recycletes MgO-C) als Ersatz für grobe Gesteinskörnung verwendet, was mit einem weiteren ökologischen Vorteil verbunden war. 

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Kurzfassung der Dissertation von Ing. Adéla Jiříčková

The construction industry is currently facing a fundamtenal challenge: to develop materials that combine high performance with a reduced environmental footprint. Traditional Portland cement (PC), although widely used, is associated with high CO2 emissions and limited chemical resistance. A promising low-carbon alternative is magnesium oxachloride cement (MOC), which provides high strengt and other advantageous properties; however, its broader application is hindered by poor water resistance and uncertain long-term stability. This dissertation, therefore, focuese on overcoming these limitations through the use of carbon nanomaterials with a partial degree of oxidation - specifically oxidized carbon nanotubes, graphene oxide , and carbon spheres prepared from waste plastics. The chosen approach combined a systematic study of the influence of these additives on hydration, microstructure, and the resulting physical and mechanical properties of cement matrices with an assessment of their environmental safety. The results demonstrated that the effect of nanomaterials is strongly dependent on the type of binder: in PC, they primarly improve the bonding of hydration products and the compactness of the microstructure, weheras in MOC, they significantly influence the crystallization of major phases and the porosity of the composite. An important contribution was also the inclusion of low-cost carbon spheres derived from waste plastics, which proved capable of enhancing MOC strength, thereby opening a pathway toward circular waste utilization. The research also incorporated experimental ecotoxicological evaluations, which showed that the releaseof carbon nanoparticles from MOC has a relatively low impact on aquatic organisms. However, toxiciity depends on the type and chemical modifications of the additive. Overall, this work provides a new perspective on the sustainable development of cement composites: it highlights that the succesul implementation of nanotechnologies in construction requires linking material performance improvements with both circular and environmental considerations. 

Kurzfassung der Dissertation von Ing. Anna-Marie Lauermannová

This dissertation investigates high-performace environmentally sustainable building composites based on highly reactove magnesium oxide. The presented work deals with the synthesis and chracterisation of composite materials based on a magnesium oxychloride cement phase 5 (Mg₃(OH)₅Cl.H₂O, MOC) matrix. Two approaches in the design and development of thesse composites are presented. In the first approach, MOC is modified with several types of layered nanomaterials in order to achieve the best possible material properties of the resulting composite material. Graphene, nanostructured alumina and molybdenum disulfide were used. The second approach, taken in order to highlight the environmental benefits of MOC-based building composites, involved using three types of waste fillers as substitues for standard silica sand, demonstrating the possibility of avoiding landfilling and giving them a secondary use. The waste materials used invluded wste carbon-bonded magnesia, waste MOC-based composites, and waste refrctory silicate bricks. All the prepared samples were thoroughly characterised in terms of their composition )phase and chemical), microstructure and morphology, structural properties (density, porosity), machenical properties (flexural and compressive strength, dynamic Young´s modulus) and properties related to water and moisture exposure (water absorption, softening coefficient, overall water resistance).