The Norwegian Public Roads Administration has a long tradition in applying various types of lightweight filling materials for road construction purposes. During the last 50 years wooden materials like sawdust and bark residue from the timber industry have been applied for such purposes. Also waste material from the production of cellular concrete blocks and LWA (Light Weight Clay Aggregate) have been widely used. Since 1972 blocks of Expanded polystyrene have been used extensively in road projects for a variety of applications also including blocks produced from re-circulated EPS material. In this connection monitoring programmes have been initiated in order to investigate the long term performance of these materials. Presently a new option is being investigated involving the use of granulated foamed glass produced by re-circulating waste glass. The maximum grain size will be some 50 mm with angular edges and the material may be produced in various densities. When placed and compacted in a drained fill the unit density of the lightest version will be some 300 - 350 kg/m3 depending on the compaction machinery and compaction efforts. On recent road projects deformations and possible variations in moisture content, unit density and grain size distribution will be monitored. In two projects in particular foamglass used temporarily in a road section will be excavated and reused in another location providing extended possibilities for monitoring material behaviour. This paper presents results from this monitoring programme and gives recommendations regarding design criteria and construction procedures related to foamglass. The application of foamed glass in road construction is also part of a larger programme in order to enhance the use of recycled material in road construction in general. For the covering abstract see ITRD E135448.
Abstract