The project of a hydro power station in the Chinese province of Henan is extreme from every point of view: a giant 3 million cubic metres of water will turn turbine generators achieving a combined output of 1,200MW of electricity. Two water reservoirs are needed to operate the pumped storage power facility, one of them located in the valley and one in the mountains. They are surrounded by retaining walls 31° steep. The main reservoir lying higher up needs lining with an asphalt seal. This challenge is taken by a modified SUPER 1800-2 paver. In close co-operation with the contractor, WIRTGEN China and VÖGELE got the paver ready to face the steep uphill task.

A transfer station positions the SUPER 1800-2 slope paver in place for the next strip

After undergoing modification into a slope paver, the SUPER 1800-2 is on the scene in Henan Province situated some 750km from Beijing, to tackle the huge job. Work on site is progressing steadily and will be completed by the end of 2007. Even for the booming Chinese building industry, this project is a kind of special challenge. And as far as local supply of electricity in Henan Province is concerned, home to 96 million people and one of China’s most populated regions, the Baoquan Power Station Project is an important investment.

Reservoirs hold 3 million cubic metres of water

The upper reservoir, with a holding capacity of 3 million cubic metres, will be flooded with water from sources in the surrounding mountains during the rainy season between July and August. The water flows downhill in massive pipes to turn four powerful turbines and is then collected in the lower reservoir. Each of these turbines generates 306MW of electricity, satisfying the region’s needs primarily during the day and at times of peak usage. At night when less power is needed across the province, water is pumped back up from the lower reservoir to the higher one to let the cycle begin anew on the next day. This way, the region will overcome bottlenecks in energy supply.

166,000m2 of asphalt seal to be paved

For sealing the water reservoir, asphalt is paved. When selecting machinery for the job, contractor IWHR (China Institute of Water Resources and Hydropower Research), headed by Dr. Hao Jutao, relied on the know-how of WIRTGEN China. WIRTGEN China together with VÖGELE and IWHR modified a SUPER 1800-2 to meet the project’s particular requirements. After undergoing technical modification, the slope paver was up to its task of laying asphalt on the huge area. For the wall of the reservoir alone, 166,000 square metres need to be lined with asphalt to provide a waterproof seal. Paving is carried out in 2 layers with a thickness of 10cm each. For the binder course, asphalt (0/19) is used with a bitumen content of 4% and for the surface course asphalt (0/12) with 7% of bitumen. The relatively high content of bitumen is required to achieve waterproofness. The SUPER 1800-2 paves 80m wide strips from bottom to top. After completion, a liquid seal 2cm thick will be sprayed on the finished lining.

High Compaction Technology performs great on the slope of 31°

It is the steep slope angle of 31° that poses a particular challenge on site. The SUPER 1800-2’s capability of acting under these extreme conditions is due to a number of technical modifications. Combined with an AB 500-2 Extending Screed in TP2 version, the SUPER 1800-2 paves vertical strips varying in width between 2.5m and 4m. On the slope, the machine operates at a speed of 1.5m per minute. A small roller is sufficient to bring about the pavement’s final density. On the Baoquan Hydro Power Station Project, an articulated HAMM tandem roller type HD 13, linked to a cable winch for safety, handles the compacting job.

A transfer station positions the paver in place

The conditions on site are extreme not only from the engineering point of view but also for the paving team headed by Dr. Hao Jutao. The team paves asphalt, strip after strip, from bottom to top. When arrived at the top, a transfer station positions the paver in place for the next strip. Attached to safety cables, the paver moves back down the slope to get ready there for its new climb. Safety first is the motto for feed of the paver with mix, too. A special shuttle vehicle driven electrically and provided with an insulated dump body supplies the paver with hot mix on the steep slope, several times for each strip.

For further Informationen please contact:

JOSEPH VÖGELE AG

Roland Schug / Martin Hilken

Neckarauer Str. 168 - 228

68146 Mannheim

Germany

Telephone: +49 (0) 621 8105 232

Fax: +49 (0) 621 8105 469

Email: Roland.Schug@voegele-ag.de

Email: Martin.Hilken@voegele-ag.de

Internet: www.voegele-ag.de