info on exterior insulation/filling material, etc.-1999

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EPS Geofoam 2001,3rd International Conference, Salt Lake City,December 2001 1 INTRODUCTION In Norway the 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 materials form the production of cellular concrete blocks and Leca(Light Expanded Clay Aggregate)have been widely used.In this connection also monitoring programmes were 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. When a major research project on frost action in soils was carried out in Norway during the period 1965 to 1973 this included the investigation of various insulation materials for frost protection of roads like 50 to 100 mm thick boards of foamed glass,extruded polystyrene(XPS)and expanded polystyrene(EPS).In this connection also fatigue tests were performed.It was then concluded that EPS material could sustain the repetitive stresses occurring in a road structure and the idea of applying EPS in greater layer thickness than boards emerged. In 1972 the Norwegian Public Roads Authorities adopted the use of EPS as a super light filling material in road embankments.The first project involved the successful reconstruction of road fills adjacent to a bridge founded on piles to firm ground.Prior to reconstruction the fills,resting on a 3 in thick layer of peat above 10 in of soft marine clay,experienced a settlement rate of more than 200 mm per year_By replacing 1 in of ordinary fill material with two layers of EPS blocks,each layer with 0,5 in thickness,the settlements were successfully halted.When placed the EPS blocks had a density nearly 100 times lighter than the replaced materials. Since then authorities in several countries have also found the method advantageous for building roads across soft ground and for other construction purposes where low loads are essential.In addition to reduced vertical loads, advantages from using EPS may also include reduced horizontal loads,simplified designs,foundations on EPS and increased speed and ease of performing construction activities.The method is now in common use in several countries in Europe,Asia and North America.At present more than 350 road projects involving EPS fills have been completed in Norway with a volume of totalling some 500,000 mi of EPS blocks. EPS does of course not represent the only solution to bearing capacity and settlement problems.Other lightweight filling materials should also be considered together with other alternatives such as replacement or displacement of the weak soil or soil improvement,piled foundations etc.Availability and cost are important factors in this connection,but in many cases the use of EPS will prove advantageous and in some cases represents the only practical solution.In a book published(1997)by PIARC,the World Road Association,lightweight filling materials in common use are presented together with case histories. MONITORING PROGRAMME Expanded polystyrene is a very stable compound chemically and no material decay should be expected when placed in the ground and protected according to the present design guidelines.Still,since the first road insulation project with EPS was performed in 1965 and the first EPS light weight embankment was constructed in 1972,EPS fills have also been monitored for long term performance along the lines followed for other lightweight filling materials used in road construction in Norway. Long term performance and durability of EPS as a lightweight filling material