Abstract
In the context of the microstructure of nano-SiO
2
cement nanocomposites, information regarding the tricalcium silicate (C
3
S) and dicalcium silicate (C
2
S) phases during the hydration reaction remains inadequate. Therefore, in this research, the effects of different SiO
2
nanoparticles contents on the microstructures, mechanical performance, and thermal stability of cement nanocomposites were investigated. The X-ray diffraction (XRD) results highlighted that the incorporation of nano-SiO
2
enhanced the microstructure of the nanocomposites by decreasing the Ca(OH)
2
, C
3
S, and C
2
S peaks, leading to a higher production of calcium silicate hydrate (CSH) products. Moreover, the intensity of the unhydrated gypsum phase increased with the increase in the nano-SiO
2
contents, which was suggestive of the retardation effect of nano-SiO
2
on the aluminate phases and aluminate reaction. Furthermore, the addition of nano-SiO
2
considerably enhanced the flexural strength and thermal stability of the nanocomposites compared to the control composites. The optimum ratio of nano-SiO
2
was 1 wt%.