摘要
分析不同掺量纳米偏高岭土改性混凝土的氯离子迁移系数、劈裂抗拉强度、经受腐蚀后质量变化率及力学强度,利用灰靶决策对四种纳米偏高岭土掺量进行优选,通过微观形貌及孔结构对其增强机理进行研究。结果表明:纳米偏高岭土的掺入可改善混凝土内部孔结构,阻断孔隙之间连通性,并促进胶凝材料水化作用,生成更多稳定的水化产物,从而提升混凝土密实性及均匀性,最终提高混凝土的抗渗性能及抗酸雨腐蚀性能;随着纳米偏高岭土掺量的增大,混凝土的抗渗性能先增大后减小;纳米偏高岭土掺量越大,混凝土的抗腐蚀性能越好;利用混合型多指标灰靶决策理论优选,7.5%纳米偏高岭土掺量下改性混凝土的抗渗及抗腐蚀性能综合最优;纳米偏高岭土能使混凝土内部水化程度提高,水化产物增多,并显著降低混凝土的孔隙率和平均孔径。
The chloride ion migration coefficient,splitting tensile strength,quality change rate after corrosion and mechanical strength of modified concrete with nano metakaolin at different dosage is analyzed,and the dosage of four kinds of nano metakaolin is optimized by gray target decision.The strengthening mechanism is studied through micro morphology and pore structure.The result shows that the dosage of nano metakaolin can improve the internal pore structure of concrete,block the connectivity between pores,promote the hydration of cementitious materials,generate more stable hydration products,thus improving the compactness and uniformity of concrete,and ultimately improve the impermeability and acid rain corrosion resistance of concrete.With the increase of nano metakaolin content,the impermeability of concrete first increases and then decreases;the higher the content of nano metakaolin,the better the corrosion resistance of concrete;the impermeability and corrosion resistance of modified concrete with 7.5%nano metakaolin content are optimized by the mixed multi-index grey target decision-making theory;nano metakaolin can improve the hydration degree of concrete,increase the hydration products,and significantly reduce the porosity and average pore size of concrete.
作者
鲍露
BAO Lu(China Railway 18th Bureau Group No.2 Engineering Co.,Ltd.,Tangshan 064000,Hebei,China)
出处
《路基工程》
2023年第4期87-93,共7页
Subgrade Engineering
关键词
纳米偏高岭土
多指标灰靶决策
微观形貌
孔结构
密实性
nano metakaolin
multi-index grey target decision
micromorphology
pore structure
compactness
