Development of nanofiber reinforced reactive magnesia-based composites for 3D printing

Nanofiber reinforced reactive magnesia-based composites (nano-FRMC) with varying nanofiber contents (0–0.6%) at different water to binder ratios (0.35–0.50) were developed. Fresh properties (slump, flow diameter, degree of levelling) and mechanical performance were systematically studied. Experimental results revealed that the inclusion of nanofibers altered the shape stability of the mixtures and accelerated the convergence of the degree of leveling. Mechanical tests revealed an optimum nanofiber content for achieving the highest compression strength associated with fiber bridging and networking effects. Thermogravimetric analysis and scanning electron microscopy tests revealed the effect of nanofibers on the enhanced formation of hydrate and carbonate phases and microstructural evolution. A thixotropy index was introduced to model the variation of slump and flow diameter subjected to jolting, under the combined effect of nanofiber content and water to binder ratio. Agreement was achieved between predicted and experimental results, deepening the understanding of nano-FRMC for 3D printing applications.