The Effect of Nano Silica on Porosity and Strength

Date of Award


Degree Name

M.S. in Civil Engineering


Department of Civil & Environmental Engineering & Engineering Mechanics


Advisor: Joseph Saliba


This research investigates the effect of nano-SiO2 on porosity and strength. In both compressive strength and porosity tests, nano-SiO2 is varied from 0 to 3% (0%, 0.5%, 1%, 2%, 3%) with the fixed percentage of silica fume at 0.4%. In addition to these tests, a base test was performed that did not include SF or nano-SiO2. However, for the flexural test, only the 0% and 1% of nano-SiO2 are tested (1% is the optimal percentage for the porosity test). Also, one specimen, which does not include either SF or nano-SiO2, is tested. Results show compressive strength increases with the increase of nano-SiO2, but this increase stops after reaching 2%. Porosity decreases when the nano-SiO2 percent increases. However, such a decrease stops after reaching 1%. An increase of 0.5% of nano-SiO2 contributes to reducing the porosity by 40%, compared to a specimen that has 4% of silica fume and 0% of nano-SiO2. However, an increase of 1% of nano-SiO2 contributes to reducing the porosity by only 2.4% because nano-SiO2 particles are more beneficial on the surface layer. Consequently, most of the nano-SiO2 particles that are in the core layers are redundant because the surface layer decreases the porosity sufficiently. The flexural strength seems to increase with the increasing percentage of nano-SiO2, compared to 4% of silica fume and 0% of the nano-SiO2 specimen.


Civil Engineering, Nanotechnology, Nano silica in Concrete, Nano Silicon Oxide in Concrete, The effect of nano silica on porosity and strength, Improve concrete porosity and strength by using Nano SiO2, the effective of Nanomaterials in Concrete porosity, nanomaterials

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