Use of waste gypsum for shear thickening of dredged soil by decarburization slag

• 作 者: Satoshi NAKAI Masayuki OZAKI Tetsuji OKUDA Wataru NISHIJIMA Mitsumasa OKADA
• 机 构: Faculty of Engineering, Hiroshima University, Japan
• 出 处: The 6th Joint China-Japan Chemical Engineering Symposium(第六届
• 发表日期: 2011年3期
• 关键词: Dredged soil Gypsum Sand mining site Solidification Steel making slag

　　Infilling sea sand mining sites using dredged soil (DS) requires avoidance of its effusion during the operation, and therefore shear its thickening or solidification is necessary.Steel making slag is one of the promising agents; however high water content of DS may be impeditive for use of steel making slag.In this study, waste gypsum-derived hemihydrate plaster (HP) was tested as a water absorber for shear thickening of DS using decarburization slag (DCSL).HP was capable of adjusting apparent water content of DS, and the use of HP resulted in 60% reduction in the amount of DCSL required to meet the target Vane shear stress (0.5 kN/m2).As the total dose of thickening agents, the combinational use of HP and DCSL achieved 40% less as compared to the case of DCSL simple use.After putting the treated DS in the artificial sea water, Vane shear stress increased and stayed constant in 30 days.The shear thickening effect of DCSL particles was dependent on grain size, and the fractions less than 2 mm-diameters were the key factor.Finally, a simple additive model was proposed to expect changes in Vane shear stress of DS.