Evaluation of Geopolymer for Stabilization of Sulfate-Rich Expansive Soils for Supporting Pavement Infrastructure
Evaluation of Geopolymer for Stabilization of Sulfate-Rich Expansive Soils for Supporting Pavement Infrastructure
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DOI：
10.1177/03611981221086650
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发表时间：
2022-05
影响因子：
1.7
通讯作者：
Jungyeon Jang;Nripojyoti Biswas;A. Puppala;S. Congress;M. Radovic;Oscar D. Huang
中科院分区：
文献类型：
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作者：
Jungyeon Jang;Nripojyoti Biswas;A. Puppala;S. Congress;M. Radovic;Oscar D. Huang
富含硫酸盐的膨胀土路基的稳定是交通基础设施工程师和从业人员持续关注的问题。一般不推荐使用传统的钙基稳定剂来处理此类土壤，因为会形成有害的反应产物，如钙矾石。硫酸盐引起的隆起会对路面造成严重的结构性破坏，并导致日常维护和修复活动的巨大支出。研究了偏高岭土基地质聚合物（GP）处理富硫酸盐膨胀土的可行性。天然土壤和人工硫酸盐丰富的土壤，石灰或GP处理时，进行了实验室研究，以评估和比较工程性能的改善，包括无侧限抗压强度，膨胀和收缩，以及弹性模量特性在不同的固化期。微观结构的研究，如场发射扫描电子显微镜和X射线衍射，进行处理后的土壤，以检测反应产物的形成。工程研究表明，GP处理增强强度和弹性模量，同时抑制钙矾石的形成和相关的溶胀-收缩处理土壤的潜力。微观结构研究表明，GP凝胶有助于通过形成均匀的地质聚合物基质来改善这些工程性能。此外，钙源的情况下抑制了在GP处理的土壤中钙矾石的形成。总体而言，研究结果表明，GPS可以作为一个潜在的替代现有的传统稳定剂处理富含硫酸盐的膨胀土。
Stabilization of sulfate-rich expansive subgrade soils is a persistent cause of concern for transportation infrastructure engineers and practitioners. The application of traditional calcium-based stabilizers is generally not recommended for treating such soils because of the formation of deleterious reaction products such as ettringite. Sulfate-induced heaving causes severe structural damage to pavements and accounts for enormous expenditure from routine maintenance and rehabilitation activities. A research study was undertaken to evaluate the feasibility of using a metakaolin-based geopolymer (GP) for the treatment of sulfate-rich expansive soil. Laboratory studies were conducted on natural soil and artificially sulfate-rich soils, when treated with either lime or GP, to evaluate and compare the improvements in the engineering properties, including unconfined compressive strength, swelling and shrinkage, and resilient moduli characteristics over different curing periods. Microstructural studies, such as field emission scanning electron microscopy and X-ray diffraction, were performed on treated soils to detect the formation of reaction products. The engineering studies indicate that GP treatment enhanced strength and resilient moduli while suppressing ettringite formation and the associated swell–shrink potential of the treated soils. The microstructural studies showed that GP gels contribute to the improvement of these engineering properties through the formation of a uniform geopolymer matrix. In addition, the absence of a calcium source suppressed the formation of ettringite in the GP-treated soils. Overall, the findings indicate that GPs could be used as a potential alternative to existing traditional stabilizers for treating sulfate-rich expansive soils.