Investigation of Polyacrylamide, Cement, and Fly Ash Additives for the Stabilization of Coastal Earth Embankment Material

Coastal embankments in Bangladesh have been suffering from repeated damages due to frequent floods and cyclones over the last few years. Stabilizing embankment soil is essential to mitigate these damages and attain sustainability. This study used the PAM additive as the primary stabilizing agent. Additionally, other stabilizers, that is, cement and fly ash, were mixed in different ratios with PAM to study its combined effect on enhancing soil’s physical and strength properties. Untreated soil samples were collected from the coastal area of Chattogram, Bangladesh, and were treated in the laboratory with PAM and other stabilizers with different mixing ratios. A series of geotechnical laboratory tests, that is, Atterberg limit tests, Proctor compaction tests, unconfined compressive strength (UCS) tests, etc., have been performed in a sequence on treated and non-treated soil samples to study the effectiveness of the stabilizers. The optimum mixing ratios of different stabilizers are selected by considering the workability and strength enhancement of treated soils. Various methods to prepare treated samples have been studied in detail. Variations in results have been observed while treating the soil in powder and solution forms of admixtures. The investigation shows that both workability and strength should be considered when selecting the soil and admixture ratio. The research outcome of the study also indicates that the soil’s physical and strength properties improved when the stabilizers were used as a combination of different mixing ratios rather than using the PAM alone.