李召峰, 陈经棚, 杨磊, 齐延海, 张健, 张晨. 石粉对赤泥基注浆材料的影响机制[J]. 工程科学学报, 2021, 43(6): 768-777. DOI: 10.13374/j.issn2095-9389.2020.12.01.005
引用本文: 李召峰, 陈经棚, 杨磊, 齐延海, 张健, 张晨. 石粉对赤泥基注浆材料的影响机制[J]. 工程科学学报, 2021, 43(6): 768-777. DOI: 10.13374/j.issn2095-9389.2020.12.01.005
LI Zhao-feng, CHEN Jing-peng, YANG Lei, QI Yan-hai, ZHANG Jian, ZHANG Chen. Influence mechanism of limestone powder on red mud-based grouting material[J]. Chinese Journal of Engineering, 2021, 43(6): 768-777. DOI: 10.13374/j.issn2095-9389.2020.12.01.005
Citation: LI Zhao-feng, CHEN Jing-peng, YANG Lei, QI Yan-hai, ZHANG Jian, ZHANG Chen. Influence mechanism of limestone powder on red mud-based grouting material[J]. Chinese Journal of Engineering, 2021, 43(6): 768-777. DOI: 10.13374/j.issn2095-9389.2020.12.01.005

石粉对赤泥基注浆材料的影响机制

Influence mechanism of limestone powder on red mud-based grouting material

  • 摘要: 为明确石粉掺合料对地聚物材料的作用机理,以赤泥基注浆材料为研究对象,系统研究了石粉掺量和粒径分布对赤泥基注浆材料浆体性能、力学性能和微观结构的作用规律,并结合X射线衍射仪(XRD)、压汞仪(MIP)和扫描电镜(SEM)等微观测试手段分析其作用机理。研究表明,结石体力学强度随石粉掺量的上升先增大后减小,当石粉的质量分数为5%时抗压强度最高,3 d时可达5.65 MPa,抗压强度提升幅度为18.94%,同时浆液泌水率上升幅度仅为9.85%,且28 d结石体孔隙率降低了18.35%,因此,5%为石粉在赤泥基注浆材料中的最佳质量分数。在石粉最佳质量分数条件下,随着石粉平均粒径减小,浆液凝结时间及泌水率均呈现下降的趋势;当石粉平均粒径达到8 μm时,石粉“填充效应”和“成核效应”作用尤为明显,浆液黏度突升,且3 d和28 d试样强度分别提升了11.86%和10%,故石粉平均粒径越小,其对赤泥基注浆材料的提升作用越显著,赤泥基注浆材料的最佳粉料质量配比为赤泥47.5%,矿粉47.5%,石粉5%;微观分析证实,石粉在浆液水化历程中以物理特性参与其中,为Na2O–SiO2–Al2O3–H2O凝胶(N–A–S–H), 水化硅铝酸钙凝胶(C–A–S–H)和水化硅酸钙凝胶(C–S–H)等凝胶提供成核位点,供地聚物凝胶沉淀和生长,加速浆液水化。

     

    Abstract: Considering the unstable performance of geopolymeric materials due to the large fluctuation of the raw-material composition and the high alkalinity of the system, this study investigated the effect of limestone powder on red mud–based geopolymeric grouting materials; moreover, the influence mechanism was analyzed via X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM). Also, the study provided some reference to reduce the storage of red mud and realize the collaborative utilization of limestone powder and red mud–based grouting materials. The results show that the mechanical strength of specimens first increases and then decreases with the increase in the limestone powder content. The compressive strength of the specimen with 5% limestone content was the best: the 3-day compressive strength could reach 5.65 MPa, which was 18.94% higher than that of the specimen with 0% limestone powder content. Moreover, the slurry bleeding rate of the 5%-limestone specimen was only 9.85% higher than that of the 0%-limestone specimen, and the porosity of the former on day 28 was 18.35% lower than that of the latter. Therefore, 5% is the best content of limestone powder in red mud–based grouting material. When the mean particle size of limestone powder was 8 μm, the “filling effect” and “nucleation effect” of specimens were significant, and the slurry viscosity rose sharply; the compressive strengths of day-3 and day-28 samples increased by 11.86% and 10% than those of the corresponding bulk-limestone samples, respectively. Thus, the smaller the mean particle size of limestone powder, the more significant the improvement effect of red mud based grouting material. The optimum proportion of red mud–based grouting materials was 47.5% red mud, 47.5% blast furnace slag, and 5% limestone powder. The macro analysis confirms that limestone powder participates in the slurry hydration process, providing nucleation sites for N–A–S–H, C–A–S–H, and C–S–H gel, which can be used for geopolymer gel precipitation and growth and accelerate the slurry hydration.

     

/

返回文章
返回