Why China’s Jingjintang Expressway is shouldering heavy loads again.
Colossal investments enabled China’s network of motorways to be expanded to over 25,000 kilometres of road. Many of these roads were initially designed for a much lower traffic volume than is actually using them today, a fact that necessitated a growing number of rehabilitation projects in addition to new construction.
One of the roads in urgent need of repair is the Jingjintang Expressway, which links the port of Tianjin with the capital of Beijing. 35,000 vehicles per day, including 10% of heavy traffic, put a much higher strain on the road than originally planned. The heavy traffic had caused in particular the right-hand lane to literally fall apart. The motorway owners therefore decided to hot recycle several sections of the 143 km long road. The benefits of this method: Instead of placing a new surface course across the full road width, rehabilitation was restricted to the damaged slow lane. The option of replacing the entire pavement would also have been much more expensive.
One of the sections chosen for hot recycling was a 30 km long stretch of road between Caiyu and Dayafang. The method was put to the test at a recycling depth of 4 cm and a working width of between 3.8 m and 4 m. The Wirtgen Remixer 4500 followed right behind a panel heating machine HM 4500, heating the pavement further with its heater panels. The machine then scarified the heated asphalt pavement material and conveyed it to the integrated twin-shaft compulsory mixer. In the mixer, the existing material was thoroughly mixed with 8% to 10% of virgin mix and 0.4 l to 0.6 l of bitumen per square metre. The fully recycled surface course material was then placed by the machine’s integrated paving screed. The recycling train worked at an advance speed of between 1.6 to 2.2 m/min. Heavy traffic was using the road again just a few hours after completion of the compacting operation.
The owners of the Jingjintang Expressway were highly satisfied with the results – both with a view to the fast “in-situ” construction method and with the fact that only the damaged traffic lane needed to be closed for a very short while.
|Job site:||Jingjintang Expressway, China|
|Paving speed:||1.6 - 2.2 m/min|
|Paving width:||3.8 - 4.0 m|
|Addition of virgin mix:||8 - 10%|
|Addition of bitumen:||0.4 - 0.6 l/m²|