Recent advances in the usage of recycled materials in transportation geotechnicsKeynote Address

Priority waste materials currently generated in Australia include construction wastes, demolition wastes, glass fines, waste tyres, plastics, industrial wastes and organic wastes. The increase in generation of these wastes have led to significant research over the past decade on the reuse of recycled waste materials in geotechnical engineering applications. An estimated 7.9 Mt of wastes, which accounts for 36% of Australia’s current annual landfilled waste, have the potential to be diverted into civil engineering applications, such as for the construction of roads, railways and land reclamation projects. Recycled materials have been evaluated in the laboratory and new specifications successfully developed, to incorporate their usage in pavement geotechnology and ground improvement applications. Recycled materials are increasingly being used in unbound and stabilised pavement applications. In addition, industrial wastes such as fly ash and slag have also been evaluated in recent years as alternative binders to cement in pavement and ground improvement applications. This paper discusses recent advances in the usage of recycled materials in transportation geotechnics, with reference to case studies of recycled materials usage in Australian projects. Ground improvement projects, comprising of the installation of ground inclusions in waste materials, in an international railway and an airport land reclamation project are also discussed.