Comparison of strength characteristics of non-salt and salt-rich stabilized dredged soils

摘要

Marine dredged soils taken from navigation channels or construction sites of coastal area usually have a lot of salt in clayey soils. High salt concentration of clayey soil has a negative effect on the strength characteristics of stabilized dredged soils. This paper focuses on the effect of salt and bottom ash on the strength development of stabilized marine dredged soil. The composite geomaterial (CGM) in this study consisted of dredged soil, cement and bottom ash. Several pairs of CGM with non-salt or salt-rich dredged soil, noted as CGM-N and CGM-S, respectively, were mixed with various bottom ash contents (i.e., 0, 50, and 100%) to investigate their strength characteristics. The microstructures and the strength characteristics of CGM-N and CGM-S were investigated using scanning electronic microscope (SEM), and unconfined compression test at 7 and 28 days curing time. It is found that salt concentration of clayey soil contributes not only to change microstructure of cement-stabilized soil but also to reduce significantly the strength of mixture. Test results also indicate that the strength of CGM increases with an increase of bottom ash content due to bond formation and interlocking effect of bottom ash particles. The strength of CGM-N is greater than that of CGM-S at a given bottom ash content due to the more pozzolanic reaction.