Mechanical Properties of concrete mixed with SiO2 and CaCO3 nanoparticles

The split tensile strength and compressive strength of concrete mixed with SiO2 and CaCO3 nanoparticles have been experimentally studied. SiO2 nanoparticles as a partial cement replaced by 0.5, 1.0, 2.0 and 3.0 wt.% and CaCO3 nanoparticles by 1.0 and 3.0 wt.% were added partially to concrete. Curing of the specimens has been carried out for 7, 28, 78 and 128 days after casting. SiO2 nanoparticle as a partial replacement of cement up to 3.0 wt.% could accelerate formation of CSH gel at the early ages and hence increase the split tensile strength and compressive strength. The optimal replacement level of cement by SiO2 nanoparticles for producing concrete with improved strength was set at 2.0 wt.%. CaCO3 nanoparticles as a partial replacement of cement up to 3.0 wt.% could consume crystalline Ca(OH)(2) and accelerate formation of calcium carboaluminate hydrate at the early ages and increase the split tensile strength and compressive strength. The optimal replacement level of cement by CaCO3 nanoparticles for producing concrete with improved strength was set at 3.0 wt.%.