摘要
基于试验分析纳米二氧化硅(NS)体积掺量(0%、0.5%、1.0%、1.5%、2.0%、2.5%)对混凝土材料孔隙结构、抗氯离子渗透性、抗冻融性能及力学性能的影响规律,以此确定混凝土材料中纳米二氧化硅的最佳掺量。结果表明:(1)试件内部孔隙直径主要为0.0006~0.0350μm,相较于NS掺量0%试件孔隙率,NS掺量在0.5%、1.0%、1.5%、2.0%、2.5%时试件孔隙率降幅分别为16.48%、23.94%、28.17%、30.51%、32.07%,NS的掺入能够有效改善混凝土材料内部孔隙结构,降低孔隙率,但过量NS对试件孔隙率影响不再显著加大。(2)随着NS颗粒含量的增加,混凝土抗氯离子渗透性能逐渐增强。NS的掺入可使有害孔隙转化为无害孔隙,提高混凝土试件的抗氯化物渗透性。(3)盐冻作用下试件会产生物理及化学损伤,试件相对动弹性模量随之降低。NS颗粒的掺入能够增强混凝土材料抗冻融性能,且掺量在1.5%时提升效果最显著。(4)与素混凝土力学性能相比,NS的掺入能够显著改善混凝土材料抗压强度及拉伸强度,应力增幅均呈先增大后减小的变化趋势,且NS掺量在1.5%时试件强度增幅最高,说明适量的NS掺入能有效改善混凝土材料力学性能,而过量NS掺量使得混凝土强度提升不再显著。
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 0.035μm.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.
作者
高翠
GAO Cui(School of Transportation and Architectural Engineering,Hefei Economic and Technical Vocational College,Hefei 230000,China)
出处
《安阳工学院学报》
2025年第6期93-99,共7页
Journal of Anyang Institute of Technology
关键词
纳米二氧化硅
混凝土
孔隙结构
渗透性
相对动弹性模量
力学性能
nano-silica
concrete
pore structure
permeability
relative dynamic elastic modulus
mechanical properties
