The effects of Nano-Fe₂O₃ on the mechanical, physical and microstructure of cementitious composites

In this study, properties of cement composites and mortars were investigated in presence of Nano-Fe₂O₃ as their modifier. Cement composites were synthesized using the sol-gel method with tetraethylammonium orthosilicate as the complex legend. Subsequently, Nano-Fe₂O₃ was added at 2, 4, and 6 wt% dosages to the cement composite, while for mortars 2, 3 and 4 wt% of Nano-Fe₂O₃ dosages were used. FTIR and XRD tests were conducted to analyze the phase composition, molecular, and microstructure of cement composites, additionally, the effects of adding Nano-Fe₂O₃ on compressive and flexural strengths of mortars were investigated. The results indicated a change in the phase composition of the molecular-structure of cement composites, leading to stronger bonds in silicate network with more ordered arrangement in the presence of nanoparticles. The formation of three-membered silicate rings was also evident in composite samples containing higher amounts of Nano-Fe₂O₃ (i.e. 4 and 6 wt%). The microstructure analysis revealed that samples with Nano-Fe₂O₃ had a denser structure with a smaller pore size in comparison with control samples. The mechanical performance of mortar samples were enhanced with the incorporation of Nano-Fe₂O₃, where 3 wt% dosage was identified as the optimum.