Paving surface seal on dumping ground for refuse is not a simple job. Due to the steep slope, the paver normally works in a horizontal direction around the refuse heap while a heavy whinched vehicle, mostly an excavator, secures the paver. German contractor Kirchhoff, however, chose a different approach for sealing the dumping ground at Horb-Rexingen in southwestern Germany.

The company relied on the high tractive power of the tracked SUPER 1900 and paved the asphalt seal in vertical strips from the bottom upwards – with no time-consuming and costly securing of the paver.

In many countries, dumping grounds are much more complex systems than is normally perceived by the general public. German environmental protection laws, for instance, stipulate a number of different impervious layers for the sealing of dumping grounds – from below prior to opening and from above after shut-down. It is not enough just to let the grass grow. For reasons of cost-efficiency, this job is increasingly done by road pavers. Sealing a mountain of refuse is a real challenge due to the very steep slope.

But not so at Horb-Rexingen. Thanks to its excellent tractive effort, a VÖGELE SUPER 1900 of standard design combined with an AB 500 screed in TP2 version managed the steep slope all on its own.

The paver laid the seal from the bottom upwards in trapezoidal strips matching the contours of the object. Dumping grounds subject to European standards have to meet with a whole series of requirements as regards in-service performance on the one hand and eco-friendliness on the other. Particular importance is attached to the functionality of the individual sealing layers. The bottom layers serve to protect the ground from ingress of seeping water. The top layers seal the dumping ground like a lid after it has been shut down. Individual layers consist of loam, recycled asphalt,crushed stone and finally a special asphalt mix.

At Horb-Rexingen, contractor Kirchhoff paved, among others, recycled granulated asphalt, milled off by a WIRTGEN Cold Milling Machine, to which binder had been added in a WIRTGEN KMA 200 Cold Recycling and Mixing Plant. The SUPER 1900 placed no less than 40,000 tonnes of this bituminous bound base course material. For paving both base and top layer, supply of the paver with mix was by very light feed lorries.

For the top layer, the SUPER 1900 placed some 12,000 tonnes of mix used specially for the sealing of dumping ground. This special mix features a bitumen content of about 7%, which is more than in usual mixes. Despite the steep slope, the SUPER 1900 could make use of High Compaction Technology. Thanks to the high level of pre-compaction achieved this way, no more than 5 to 6 passes were required for extra compaction by rolling. After completion of the job the area will be renaturalized and be a flying site for a local Model Aeroplane Club. Thanks to the long lasting perfect seal, the aircraft will always be surrounded by fresh air as they sail through the air.

Area Paved:
60,000m²

Materials:
40,000 tonnes of bituminous bound base course material, 12,000 tonnes of special mix for asphalt seal on dumping ground

Slope Gradient:
33%

Pave Width:
trapezoidal strips measuring 4.8m (bottom) and 2.8m (top)

Layer Thickness:
8cm

Pave Speed:
3m/min

Daily Laydown Rate:
300–350 tonnes

High Compaction Configuration:

Tamper: 1,600rpm, stroke length 4mm

Pressure Bars: 90bar

Equipment:
VÖGELE SUPER 1900 with AB 500 screed in TP2 version, WIRTGEN Cold Recycling and Mixing Plant KMA 200