An Experimental Study On Concrete Containing Nano And/Or Micro Silica

The effect of using Portland cement, nano silica (NS) and /or micro silica on the mechanical and physical properties of concretes containing fine aggregate only is investigated. Two groups divided into five series each have been designed and tested. The first group was containing the nano-silica only, while the second group contained different ratios of nano silica and a constant content of 8 % of silica fume (SF) (by weight) as partial replacement of cement. Water cementations ratio (w/c) of all mixtures was constant and equal to 0.22. The cement content in all series was 800 kg/m3. Commercially available nano silica (NS) was used in the mixture for the partial substitution of cement at ratios of 0, 0.5, 1.0, 2 and 3% by weight. It was found that the addition of nano –silica is significantly enhance compressive, tensile and modulus of elasticity of concrete. From the test results obtained it has been noted that the mix containing 2 % possess significantly improved mechanical properties, furthermore, the group samples of concrete containing binary cementations nano-silica and silica fume showed better results than concrete containing nano silica only.