The Solidification Effects Of Admixing Activated Steel Slag With Dredged Marine Silts

CHEE-MING, CHAN (2016) The Solidification Effects Of Admixing Activated Steel Slag With Dredged Marine Silts. In: Fifth International Conference On Advances in Civil and Structural Engineering - CSE 2016, 12-13 March,2016, Kuala Lumpur, Malaysia.

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Abstract

Regular dredging works are necessary for the development of coastal regions and the maintenance of shipping channels. However indiscriminate disposal of the dredged soils in open waters can cause severe and irreversible impact on the marine ecosystem. It is therefore desirable to transform the otherwise waste material into reusable soils, though some form of pre-treatment is necessary to improve the material’s strength and stiffness. This paper describes an exploratory work of admixing dredged marine sediments of predominantly silt contents with activated steel slag for improvement of the mechanical properties. By first identifying the optimum activation concentration of NaOH for the steel slag, the solution was next introduced to the soil-slag mixture for uniform blending. Specimens were prepared per dry weight at ratios of clay : steel slag = 3:7, 5:5 and 7:3, then left to cure for up to 4 weeks. At intervals of 3, 7, 14 and 28 days, bender element and unconfined compressive strength tests were conducted to determine the changes in strength (unconfined compressive strength, qu) and stiffness (based on P-wave velocity, vp). Generally it was found that both qu and vp increased with higher steel slag content and longer curing time, though the increment rate was dependent on the soil type. The solidified specimens also showed improved ductility with greater failure strains. In conclusion, steel slag addition to the dredged sediments could effectively strengthen and stiffen the originally weak soil structure by (1) ‘cementation’ effect of the finer slag particles and (2) ‘filler’ effect of the coarser slag particles. The combined effects were however not distinguished in the present study.

Item Type: Conference or Workshop Item (Paper)
Uncontrolled Keywords: dredged soils, solidification, steel slag, strength, stiffness, bender element
Depositing User: Mr. John Steve
Date Deposited: 27 Mar 2019 12:10
Last Modified: 27 Mar 2019 12:10
URI: http://publications.theired.org/id/eprint/993

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