Abstract: High water content in dredged silt leads to elevated costs for drying and solidification. By fully utilizing the porous water absorption of Expanded Perlite (EP), we can locally separate free water from the silt, resulting in an uneven water distribution and creating a “silt-water separation” solidification environment. Experimental results indicate that incorporating EP with silt can effectively enhance the unconfined compressive strength (UCS) of the solidified silt, but the method of incorporation affects the rate of strength increase and pore distribution. The stewing method, which involves pre-mixing EP into the silt and then adding cement after 24 hours, proves most favorable for promoting the solidification effect. After 28 days of curing, the strength of the stewing sample is 1.56 times that of the sample directly solidified with cement after EP incorporation, and 2.15 times that of the sample solidified with cement only. This indicates that the local "silt-water separation" effect facilitated by EP can effectively enhance the strength of the solidified silt. Meanwhile, hydration heat test results show that EP promotes cement hydration. According to the pore distribution curve and surface morphology images of EP-silt-solidified soil, while EP introduces porosity, it also provides growth space for hydration products, resulting in an embedded bond that forms a solidified soil skeleton between the interface of silt and EP. The method of regulating water content using EP is a physical one, which is convenient and efficient, differing from energy-intensive methods like machinery. Additionally, as a high-silica lightweight aggregate, EP exhibits good compatibility with silt and is environmentally friendly.

Key words: silt with high water content, expanded perlite, silt-water separation, internal curing