Effect of seawater curing on the mechanical properties of solidified high-water content marine dredged clay

Understanding the effects of seawater on solidified soil is crucial for its application in ocean engineering, especially when using marine dredged clay as raw material. In this study, Comparative experiments, comprising unconfined compressive strength (UCS) tests and scanning electron microscopy (SEM) analyses, were conducted under both seawater and standard curing conditions to investigate the combined effects of additives, curing environments, and seawater on soil properties. Results show that seawater significantly weakens the mechanical performance of solidified soil. Compared to standard curing, solidified soil with ordinary Portland cement (OPC) showed an average strength reduction of 38.65 % after 7 days and over 29.28 % after 28 days. In contrast, solidified soil prepared with sulphoaluminate cement (SAC) exhibited greater resistance to seawater, with strength reductions of 28.69 % after 7 days and 20.19 % after 28 days. Polyacrylamide (PAM) can enhance the early strength of solidified soil in seawater by forming a composite structure with hydration products. An increase of 0.5 % in PAM content leads to an average strength improvement of 27.03 % at 7 days and 34.61 % at 14 days. In contrast, for every 1 % increase in superplasticizer (SP) content, the soil strength in seawater decreases by 17.78 %, 11.20 %, and 9.24 % at 7, 14, and 28 days, respectively. These findings provide important insights for improving solidified soil performance in marine environments.