Silicon carbide (SiC)/cement paste nano composites with different weight ratios of SiC (1.25, 2 and 3.3 %) to cement were synthesized by chemical wet; sol– gel method. The nano structural and mechanical properties of samples are discussed in connection with the influence of size effects and other features in detail with using atomic force microscopy, scanning electron microscopy and X-ray diffraction techniques and X-powder, Nano- Surf and Williamson–Hall analysis. The obtained results show a more stable structure for cement paste/SiC composite containing 2 wt% SiC nano particles. Also, the results indicated that compressive strength and flexural strength of cement mortars increased as a result of replacement ordinary Portland cement with up to 2 wt% SiC nano particles.
