Engineering of SiO2 Nanoparticles for Optimal Performance in Nano Cement-Based Materials

The reported research examined the effect of 5-70 nm SiO2 nanoparticles on the mechanical properties of nano-cement materials. The strength development of portland cement with nano-SiO2 and superplasticizing admixture was investigated. Experimental results demonstrate an increase in the compressive and flexural strength of mortars with developed nanoparticles. The distribution of nano-SiO2 particles within the cement paste plays an essential role and governs the overall performance of these products. Therefore, the addition of a superplasticizer was proposed to facilitate the distribution of nano-SiO2 particles. Superplasticized mortars with 0.25% of selected nano-SiO2 demonstrated a 16% increase of I-day compressive strength, reaching 63.9 MPa; the 28-day strength of these mortars was 95.9 MPa (vs. strength of reference superplasticized mortars of 92.1 MPa). Increase of 28-day flexural strength of superplasticized mortars with selected nano-SiO2 was 18%, reaching 27.1 MPa. It is concluded that the effective dispersion of nanoparticles is essential to obtain composite materials with improved performance.