石膏碱激发地聚物固化黄土强度及机理

A study on the mechanical property and mechanism of loess solidified by gypsum alkali-activated geopolymer

为探究石膏碱激发粉煤灰地聚物固化黄土的力学性能及其机理,确定最佳组分比,进行无侧限抗压强度试验、X射线衍射(XRD)及扫描电子显微镜(SEM)分析.结果表明,固化黄土的强度随石膏掺量的增加而增大;石膏掺量质量分数为1.5%,熟石灰∶粉煤灰(质量比)=7∶14时,强度最大;XRD分析结果表明石膏碱激发地聚产物主要为水化硅酸钙和钙矾石,起到胶结土颗粒以及填充的作用;SEM分析进一步证明固化土体微观结构的完整性和连续性由于地聚物的生成得到提升,印证了强度规律及固化原理,为实际工程应用提供了参考.

Unconfined compressive strength test, X-ray diffraction analysis test(XRD) and scanning electron microscopy(SEM) were used here to explore the effects of gypsum activating the fly ash-based geopolymer on the mechanical property and mechanism of solidified loess and to determine the optimal proportion. The results revealed that the unconfined compressive strength of the solidified sample increased with the increase of gypsum content;when w(gypsum)=1.5% and the content ration of hydrated lime to fly ash was 7:14(mass ratio), the strength of the solidified loess reached the maximum value;XRD indicated that the products from the gypsum-alkali-activated geopolymerization were mainly C-S-H and ettringite;SEM images further proved that the integrity and continuity of the microstructure of the solidified soil were enhanced by the products of geopolymers, which confirmed the strength law and solidification mechanism and can thus provide a reference for practical engineering applications.