纤维地聚物改良土配比设计与固化效果试验研究

Experimental Study on Material Proportioning Design and StabilizationEffect of Fiber-reinforced and Geopolymer-stabilized Soils

地聚物具有快硬早强、耐久性好等优点,是土体改良的理想固化剂,但纤维地聚物改良土可期工程性能却受控于其合理材料配比设计。以偏高岭土为前驱体、生石灰和硅酸钠为碱激发材料制备地聚物材料,开展不同材料配比下的地聚物改良土力学特性试验研究,探讨地聚物理想材料配比设计,分析地聚物改良土体的最优掺量,明确玄武岩纤维掺量与长度对地聚物改良土性能的影响规律,并综合评价地聚物、纤维对土体的固化效果。结果表明,纤维地聚物改良土力学性能随地聚物掺量、纤维掺量、纤维长度增加呈现先增后减变化,当偏高岭土与碱激发剂掺比为2∶1、碱激发剂中硅酸钠与生石灰掺比为1∶0.8、地聚物在土中总掺比为15%、玄武岩纤维掺量和长度分别为0.4%和12 mm时,纤维地聚物改良土力学改良效果最为理想;固化效果对比试验则表明,纤维地聚物改良土的抗压、抗拉、抗剪强度均优于普通水泥土、石灰土和纯黏土。研究成果可为纤维地聚物改良土应用推广提供参考依据。

Geopolymer has the advantages of fast hardening,early strength,and good durability,and it is an ideal agent for soil improvement.However,their reasonable material ratio design significantly controls the expected engineering performance of geopolymer improved soil.Taking metakaolin as the precursor for preparing geopolymer materials,in which the quicklime and sodium silicate was selected as the alkali excitation materials.A series of mechanical tests of geopolymer improved soils with different material ratios was carried out to investigate the ideal material ratio design of the geopolymer,analyze the optimal content of geopolymer for soil improvement,discuss the influence of basalt fiber content and length on the performance of geopolymer improved soil,and comprehensively evaluate the solidification effect of geopolymer and fiber on the soil.The results showed that the mechanical properties of geopolymer and fiber stabilized soils were improved first and then weakened with the increase of geopolymer content,fiber content,and fiber length.When the mixing ratio of metakaolin and alkali activator was 2∶1,the mixing ratio of sodium silicate and quicklime in alkali activator was 1∶0.8,the total mixing ratio of geopolymer in soil was 15%,and the mixing amount and length of basalt fiber were 0.4%and 12 mm,the mechanical improvement of geopolymer and fiber improved soil was the best.The solidification comparison test shows that the geopolymer and fiber improved soil was superior to ordinary cement soil,lime soil,and pure clay in compressive,tensile,and shear strength.The research results can provide a reference for soil improvement using geopolymer and fiber.