湿陷性黄土地基粉煤灰-水泥复合注浆材料性能试验研究

Experimental Study on Properties of Fly Ash-Cement Composite Grouting Material in Collapsible Loess Foundation

针对运用注浆法处理湿陷性黄土地基中传统注浆材料渗透性差,成本高等问题,通过进行室内试验,研究了不同配比下的粉煤灰-水泥复合注浆加固材料的各项性能,并对其进行了物质成分及微观结构的分析。结果表明:各个龄期下的硬化浆体随着粉煤灰掺量及水灰比的增加,其初凝及终凝时间都会延长,早期抗压强度降低,但后期抗压强度仍会缓慢增长;浆体的结石率会随着粉煤灰的增加而增大,但流动度则会减小;浆体的水化产物主要为C-S-H凝胶以及Ca(OH)2。此类注浆材料具有适合的凝结时间及流动度,拥有良好的渗透能力,提高了材料的可注性,其结石率与抗压强度也保证了对湿陷性黄土地基的承载力有提升的作用。

Aiming at the problems of poor permeability and high cost of traditional grouting materials in collapsible loess foundation treated by grouting method,the properties of fly ash-cement composite grouting reinforcement materials with different proportions were studied through laboratory tests,and the material composition and microstructure were analyzed.The results show that with the increase of fly ash content and water cement ratio at different ages,the initial setting time and final setting time of hardened slurry will increase and the early compressive strength will decrease at the same time,but the compressive strength will slowly increase in the later stage.The stone rate of the slurry will increase with the increase of fly ash content,but the fluidity will decrease.The hydration products of the slurry are mainly C-S-H gel and Ca(OH)2.This type of grouting material has suitable setting time,fluidity,and great permeability,and improves the injectability of the material.The stone rate and compressive strength of this type of material also ensure that the bearing capacity of collapsible loess foundation can be improved.