Purpose

This research presents experimental results of dredged lakebed sediment-stabilised with ordinary Portland cement (OPC) and fly ash (FA) for use as pavement materials in road infrastructure. The work also proposed empirical correlations for the strength and stiffness parameters of chemically stabilised dredged sediments intended for pavement engineering.

Materials and methods

The dredged sediment was collected from the drop-off area around Phayao Lake in Thailand. The sediment’s optimal moisture content was determined by a Proctor compaction test. The OPC and FA content ranged from 3 to 10% and 5 to 20% per dry weight of sediment. The shear strength of treated sediments at different curing time was measured using the unconfined compression (UC) test.

Results and discussion

The optimum FA content proved to be most effective in generating the highest material strengths and stiffnesses from the stabilised sediments, regardless of OPC contents and curing duration. A suitable replacement ratio of cement with fly ash was 15%. The results were compared with data on other types of chemically stabilised sediments available in literature. Correlations between engineering properties and design parameters such as UCS, E₅₀, \({\upvarepsilon }_{f}\), and e_ot can be suggested based on the comprehensive experimental results.

Conclusions

Using OPC and FA as admixes together provided the greatest improvement in the strength characteristic of dredged sediment. In addition, the study presented an empirical correlation between the strength and stiffness of adding fly ash on cement-stabilised lakebed sediment for using in geotechnical and pavement works.

中文翻译：

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稳定疏浚湖底泥沙在路基建设中的再利用

目的

本研究展示了用普通波特兰水泥 (OPC) 和粉煤灰 (FA) 稳定疏浚湖床沉积物作为道路基础设施路面材料的实验结果。该工作还提出了用于路面工程的化学稳定疏浚沉积物的强度和刚度参数的经验相关性。

材料和方法

疏浚的沉积物是从泰国帕尧湖周围的落水区收集的。沉积物的最佳含水量由 Proctor 压实试验确定。每沉积物干重的 OPC 和 FA 含量范围为 3% 至 10% 和 5% 至 20%。使用无侧限压缩 (UC) 试验测量不同固化时间处理后沉积物的剪切强度。

结果和讨论

事实证明，无论 OPC 含量和固化时间如何，最佳 FA 含量都能最有效地从稳定的沉积物中产生最高的材料强度和刚度。粉煤灰替代水泥的合适比例为15%。结果与文献中其他类型的化学稳定沉积物的数据进行了比较。可以根据综合实验结果建议工程特性与设计参数（如 UCS、E ₅₀、\({\upvarepsilon }_{f}\)和e _ot之间的相关性。

结论

使用 OPC 和 FA 作为混合物一起提供了疏浚沉积物强度特性的最大改进。此外，该研究还提出了在水泥稳定的湖床沉积物中添加粉煤灰以用于岩土工程和路面工程的强度和刚度之间的经验相关性。