Experimental Study on Pore Structure and Physical Mechanical Properties of Nano-Silica Modified Concrete
GAO Cui
Abstract：To determine the optimal volume content of nano-silica(NS)in concrete,this study experimentally investigates the effects of different NS volume contents(0％,0.5％,1.0％,1.5％,2.0％,2.5％)on the pore structure,chloride ion penetration resistance,freeze-thaw resistance,and mechanical properties of concrete.The results indicate that:(1)The internal pore diameter of the specimens primarily ranges from 0.0006 to 0.035 μ m.Compared with the specimen without NS(0％content),the porosities of specimens with NS contents of 0.5％,1.0％,1.5％,2.0％,and 2.5％are reduced by 16.48％,23.94％,28.17％,30.51％,and 32.07％respectively.NS incorporation effectively optimizes the internal pore structure and reduces porosity,but the improvement becomes insignificant when NS is over-dosed.(2)Chloride ion penetration resistance of concrete gradually enhances with increasing NS content.NS transforms harmful pores into harmless ones,thereby improving the material's chloride ion penetration resistance.(3)Under salt freezing conditions,specimens undergo physical and chemical damage,resulting in a decrease in relative dynamic elastic modulus.NS addition enhances freeze-thaw resistance,with the most significant improvement observed at 1.5％NS content.(4)Compared with plain concrete,NS incorporation significantly improves compressive and tensile strengths.The stress increment first increases and then decreases,peaking at 1.5％NS content.Appropriate NS addition effectively enhances concrete's mechanical properties,while excessive NS leads to no significant further strength improvement.
Keywords：nano-silicaconcretepore structurepermeabilityrelative dynamic elastic modulusmechanical properties
Publication Date：2025-11-20
Online Publishing Date：2025-12-03(First online date of this platform, not the publication date of the document)
Pages：7( 93-99 )