Abstract Lime and/or Ordinary Portland cement (OPC) are the traditional binders used in soft soil stabilisation. However, their manufacture has a negative impact on the environment. This paper reports the results of experimental work for the optimisation of a binary blended cementitious binder (BBCB) using two types of fly ash as an alternative for use in soft soil stabilisation. The optimum content of the high calcium fly ash (HCFA) was initially determined along with the effect of grinding activation on the performance of HCFA. Subsequently, the effect of palm oil fuel ash (POFA) pozzolanic reactivity on the engineering properties of soft soil, stabilised with HCFA, was investigated by producing different binary mixtures of HCFA and POFA. Based on the Atterberg limits and unconfined compressive strength (UCS) tests, the combination of POFA with HCFA results in a considerably lower plasticity index (PI) and higher compressive strength than those obtained from the soil treated with HCFA alone. Substantial changes in the microstructure and binders of the stabilised soil over curing time were evidenced by SEM imaging and XRD analysis. A solid and coherent structure was achieved after treatment with BBCB as evidenced by the formation of C S H, portlandite and ettringite as well as secondary calcite.

中文翻译：

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使用高钙粉煤灰和棕榈油燃料灰的二元混合稳定软土

摘要 石灰和/或普通硅酸盐水泥 (OPC) 是用于软土稳定的传统粘合剂。然而，它们的制造对环境有负面影响。本文报告了使用两种类型的粉煤灰作为软土稳定的替代品来优化二元混合胶结粘合剂 (BBCB) 的实验工作结果。最初确定高钙粉煤灰 (HCFA) 的最佳含量以及研磨活化对 HCFA 性能的影响。随后，通过生产 HCFA 和 POFA 的不同二元混合物，研究了棕榈油燃料灰 (POFA) 火山灰反应性对用 HCFA 稳定的软土工程性质的影响。基于 Atterberg 极限和无侧限抗压强度 (UCS) 测试，与仅用 HCFA 处理的土壤相比，POFA 与 HCFA 的组合导致显着更低的塑性指数 (PI) 和更高的抗压强度。SEM 成像和 XRD 分析证明了稳定土壤的微观结构和粘合剂随固化时间的显着变化。用 BBCB 处理后获得了固体和连贯的结构，如 CSH、硅酸盐和钙矾石以及次生方解石的形成所证明的那样。