To investigate the possibility of utilization of dredged soil and converter steel-making slag for coastal environmental improvement works, the experimental evaluation of dredged soil mixed with converter steel-making slag was executed. On this study, the following characteristics about mixture were confirmed that strength of soft dredged soil was improved by hydration reaction, the up of pH value of surrounding seawater were controlled, and the quantity of phosphorus elution from dredged soil was decreased. In addition, in the examination for the mix proportion, it was confirmed that f-CaO/W (ratio of quantity of free-CaO and quantity of water in the unit mixture) and D-Si/W (ratio of quantity of dissolvable silicic acid and quantity of water in the unit mixture) were parameters to influence strength of mixture.
