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Engineering and microstructure properties of contaminated marine sediments solidified by high content of incinerated sewage sludge ash

Authors :
Xin Chen
Qiang Xue
Chi Sun Poon
Jiang-Shan Li
Daniel C.W. Tsang
Yifan Zhou
Qiming Wang
Source :
Journal of Rock Mechanics and Geotechnical Engineering.
Publication Year :
2020
Publisher :
Elsevier BV, 2020.

Abstract

Management of incinerated sewage sludge ash (ISSA) and dredged contaminated marine sediments (CMSs) is a great challenge for Hong Kong and other coastal cities due to limited landfilling capacity. The present study investigates the use of high content (20% of sediment by mass) of ISSA in combination with cement/lime for solidification/stabilization (S/S) treatment of CMSs to provide a way to reuse the wastes as construction materials. The results showed that ISSA being a porous material was able to absorb a large amount of water rendering a more efficient solidification process of the marine sediment which normally had a very high water content (∼80%). The S/S treatment improved the engineering properties of the sediment, but reduced the workability, especially for the lime-treated samples. Lime can be used to replace ordinary Portland cement (OPC) for better heavy metal immobilization and carbon emission reduction. The hardened sediment samples prepared with 10% of lime and 20% of ISSA could attain a strength of 1.6 MPa after 28 d of curing. In addition, leaching tests confirmed that there was no environmental risk induced by these stabilized materials. The formation of hydrated cementitious compounds including calcium silicate hydrate (C–S–H)/calcium aluminate silicate hydrate (C-A-S-H)/hydrocalumite/calcite was mainly responsible for the strength development in the ISSA/lime-treated sediments.

Details

ISSN :
16747755
Database :
OpenAIRE
Journal :
Journal of Rock Mechanics and Geotechnical Engineering
Accession number :
edsair.doi...........479af23be498b33028a4dd870d18c984