Repurposing of stabilised dredged lakebed sediment in road base construction

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. 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. 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 eot can be suggested based on the comprehensive experimental results. 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.