The High Coast Bridge is one of the world's longest suspension bridges. The waterproofing and pavement for this bridge had to be chosen with care. A lowest average temperature of minus 20 degree centigrade, a minimum temperature of minus 40 degree centigrade and a maximum temperature of plus 30 degree centigrade have been recorded in this region of Sweden. The waterproofing and pavement system chosen for the High Coast bridge consists of an epoxy primer system, an SBS-modified bituminous sheet layer, coarse aggregate mastic asphalt with SBS-modified bitumen and split mastic asphalt with SBS-modified bitumen and fibres. Various waterproofing and pavement products and systems were tested in the research project, both separately and in different combinations for evaluation. Laboratory testing was performed at the Swedish National Road and Transport Research Institute (VTI), starting in 1992. Testing covered characteristics and performance of the various products and systems at low and high temperatures. Important parameters studied for total built-up systems included adhesion (to steel deck and between layers), shear and sliding resistance. Systems with SBS-modified bituminous sheet (3.5 mm thick), SBS-modified fine aggregate mastic asphalt (4 mm) and conventional fine aggregate mastic asphalt (4 mm) were compared. In 1993, eight different systems were laid on a steel bridge at Pitsund (further north than the High Coast Bridge) for evaluation on site and laboratory testing at VTI. Fatigue tests of the entire waterproofing and pavement system were performed for four possible systems and the reference system at the Otto Graf Institute (FMPA) in Stuttgart. Testing was performed in accordance with the German ZTV-BEL ST-92 "Dauerschwellbiegepruefung", but at temperatures from minus 30 degree centigrade to plus 30 degree centigrade. The public procurement was completed in July 1996. The system was laid during late summer and autumn of 1997. Quality control testing was performed. Samples of all products used were taken during work on the bridge. (Author/publisher)
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