Effects of Steel Slag Content and Curing Time on Compressive Strength of Underwater Compacted Coal Wash

Abstract

The reclamation project at the Outer Harbor of Wollongong's Port Kembla, Australia, involves compaction of a large volume of granular fill material either under submerged or dry conditions. Due to environmental concerns (e.g. lack of suitable landfill space to dispose industrial wastes, conservation of natural resources etc) and the large volume reclamation project, Port Kembla Port Corporation is considering the use of locally abundant granular wastes of coal wash (CW) and steel furnace slag (SFS) as an alternative to conventional and costly fill materials. Although numerous studies have been reported on the geotechnical characterization of granular industrial wastes, only few information is available to comprehensively describe their compressive and mechanical behavior under submerged conditions. This paper reports on results of a series of unconfined compression strength (UCS) tests performed to investigate the effects of SFS content and curing time on the strength properties of underwater compacted mixtures of CW and SFS. For various mixtures kept submerged in seawater for a curing time of 7, 14 and 28 days, it was found that UCS strength properties increase with SFS content and The reclamation project at the Outer Harbor of Wollongong's Port Kembla, Australia, involves compaction of a large volume of granular fill material either under submerged or dry conditions. Due to environmental concerns (e.g. lack of suitable landfill space to dispose industrial wastes, conservation of natural resources etc) and the large volume reclamation project, Port Kembla Port Corporation is considering the use of locally abundant granular wastes of coal wash (CW) and steel furnace slag (SFS) as an alternative to conventional and costly fill materials. Although numerous studies have been reported on the geotechnical characterization of granular industrial wastes, only few information is available to comprehensively describe their compressive and mechanical behavior under submerged conditions. This paper reports on results of a series of unconfined compression strength (UCS) tests performed to investigate the effects of SFS content and curing time on the strength properties of underwater compacted mixtures of CW and SFS. For various mixtures kept submerged in seawater for a curing time of 7, 14 and 28 days, it was found that UCS strength properties increase with SFS content and curing time, while volumetric expansion became insignificant within one week.