纳米二氧化硅对碱矿渣水泥泛碱的影响

Effect of Nano-silica on Alkali-activated Slag Cement Efflorescence

碱矿渣水泥因具有能耗低、二氧化碳排放低、性能优越等优点成为近年来建筑材料领域的研究热点。但其泛碱现象,影响了碱矿渣水泥的实际应用。本文旨在将纳米二氧化硅掺入碱矿渣水泥中,抑制其泛碱。研究了纳米二氧化硅掺入方式对碱矿渣水泥抗压强度和泛碱的影响,利用扫描电镜(SEM)、水化热测定、汞压入法(MIP)等技术分析了纳米二氧化硅对碱矿渣水泥泛碱的抑制机理。结果表明,纳米二氧化硅最佳掺入方式为超声分散。此外,掺加纳米二氧化硅可有效促进碱矿渣水泥的水化进程及水化程度,改善碱矿渣水泥硬化浆体微观结构,优化碱矿渣水泥硬化浆体的孔径尺寸分布,提高硬化浆体密实度,增加碱矿渣水泥的抗压强度,从而有效抑制碱矿渣水泥泛碱。

Alkali-activated slag cement has become a research hotspot in the field of building materials in recent years due to its advantages of low energy consumption,low carbon dioxide emission and superior performance.However,the efflorescence phenomenon of alkali-activated slag cement affects its practical application.The aim of this paper is to add nano-silica into alkali-activated slag cement to restrain its efflorescence.The influence of nano-silica on the compressive strength and efflorescence of alkali-activated slag cement was studied.The results show that ultrasonic dispersion of nano-silica is the best way of adding nano-silica.In addition,the incorporation of nano-silica effectively promotes the hydration process and hydration degree of alkali-activated slag cement,improves the microstructure of alkali-activated slag cement hardened paste,optimizes the pore size distribution of alkali-activated slag hardened paste,increases the hardened paste density and enhances the compressive strength of alkali-activated slag cement,thus effectively inhibits the efflorescence of alkali-activated slag cement.