POLYSTYRENE AS AN ULTRA-LIGHTWEIGHT ENGINEERED FILL

The paper reviews the development of polystyrene as a fill material. The manufacturing process to form polystyrene is briefly outlined and related to the properties of the various grades and forms of polystyrene. The classification of polystyrene into grades according to stress/strength is outlined, as are the physical properties of the various grades. The properties illustrated and discussed include: a) density; b) behaviour under uniaxial compression; c) shear strength and frictional resistance; d) water absorption; e) resistance to chemical and biological attack; f) combustibility; and g) deterioration due to ultra violet light. Design principles currently recommended in the United Kingdom and Europe for polystyrene fills are discussed, in particular, the means of protecting polystyrene from damage in service. Guidance is given on the detailing of polystyrene fill in design and on practical construction aspects. The paper concludes with an assessment of the potential uses for polystyrene fill in the design of engineered fills, highlighting the advantages over other lightweight fills. (A) For the covering abstract see IRRD 859718.