Sydney, Australia -- Graco sprayers and hydraulic proportioners from Australian Urethane Systems (AUS) were used to carry out essential waterproofing and resurfacing work on the Sydney Harbour Bridge.
The bridge is listed in the Guinness Book of Records as the world's widest long-span bridge, with a total length of 1149 metres and more than 160 000 vehicles crossing it each day, AUS said in a 17 Aug news release.
The company said that after 80 years, the bridge required essential waterproofing and resurfacing work, which involved stripping the original concrete deck. Key objectives of the resurfacing and waterproofing work included creating a smoother, more durable road surface, decreasing road noise, reducing risk of corrosion and structural damage on the bridge deck, and rejuvenating the bridge while also minimising the need for future repairs.
AUS used three Graco XP70 plural-component sprayers and four Graco Reactor H-XP3 hydraulic proportioners for adhesive and polyurethane spraying. Everything including the material, generators, compressors and Graco equipment was set up on trucks that travelled down one lane while spraying the adjacent lane.
A three-layer polyurethane waterproofing system was applied to the concrete deck of the north and south approach spans with the first primer layer applied using a power roller, followed by the polyurethane waterproofing layer and the final primer layer applied by manual spraying.
The company then sprayed heated crumbed rubber bitumen onto the concrete deck of the arch span to provide a waterproofing seal. It then spread aggregate over this, following which the asphalt was applied.
The essential bridge maintenance work was completed over two weekends in January 2012, with the entire waterproofing and resurfacing completed 10 hours ahead of schedule, AUS said.