The paper 'Some Geotechnical Properties of Waste Glass', (Ground Engineering April 2000) was interesting and provides details of ongoing work.
In addition to the conclusions drawn it would be helpful if the authors could provide some details of other useful material properties for the longer term behaviour related to the viscous nature of glass.
One can posit temperature, creep and associated deformations as possible subjects for research.
NR Somers, consultant, Sidcup, Kent Author's response: The work carried out on glass was part of a pilot study looking at the possibility of using waste glass as vertical drains for use in liquefaction mitigation.
The preliminary study therefore concentrates on the permeability and rigidity of glass drainage columns under cyclic triaxial load.
Early test results indicate that the basic properties of the waste glass will fulfil these requirements.
The investigation has not yet been extended to look at long-term behaviour but this is a necessary progression of the work and your comments are gratefully acknowledged.
In particular, as suggested, further work is required to ascertain creep and deformation effects associated with particle crushing and rearrangement under sustained load.
J Blewett, Department of Civil and Offshore Engineering, Heriot-Watt University, Edinburgh