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Η πορεία της ενυδάτωσης των δομικών υλικών μέσω διάφορων τεχνικών (Bachelor thesis)

Τσαρούχα, Μαρία/ Tsaroucha, Maria

This thesis studies the effect of air nanobubbles, in combination with carbon nanotubes and graphene nanosheets, on the course of cement hydration. Six (6) different samples were prepared containing Portland cement type II 32.5, to which an aqueous solution of drilling water was introduced at a w/c ratio of 0.5, with or without nanobubbles as well as with or without one of the above nanomaterials. These samples were examined on days 1, 2, 3, 7 and 28 of hydration. The analysis of the samples was carried out using XRD, Micro-CT and FTIR techniques, to investigate the crystalline phases, the change in porosity, as well as their chemical composition. The XRD results showed that when nanoparticles are added, the phases of the cement do not change, but the hydration reactions are accelerated, resulting in faster stabilization of the components. Porosity was examined through Micro-CT, which highlighted the significant reduction in porosity in the samples with nanoparticles. Where nanobubbles and nanomaterials act synergistically, the greatest improvement in microstructure is shown. Through FTIR, it was confirmed that introducing nanobubbles and/or carbon nanomaterials does not change the chemical composition of the cement at the molecular level, while the only change observed at the end of the days is the reduction of the hydroxyl curve and the water bending, as the free water in the sample decreases. Overall, this research demonstrated the synergistic importance of nanobubbles and carbon nanomaterials since dispersion is improved, active nucleation sites are increased and a denser microstructure results, which makes the modified cement more durable and paves the way for the examination of mechanical properties.