An environmentally friendly method for road rehabilitation

A cold recycling paving train featuring the core technology of the new Wirtgen W 240 CR carried out the structural rehabilitation of a road In Tangshan City (China) with the cold recycling method.

A successful début for a Wirtgen W 240 CR cold recycler: deployed for the first time for the rehabilitation of the Yingxiang Road in Tangshan City in Hebei Province, the new machine did a great job right from the start. The high-quality, resource-friendly cold recycling layer produced by the combination of the W 240 CR, a Vögele SUPER 2100-3 paver and a Hamm 320 compactor fulfilled all requirements and clearly impressed customers, users and the contracting authorities alike.

Cold recycling with the W 240 CR in Tangshan City
Streumaster binding agent spreader
Water tanker
Tanker with bitumen or bitumen emulsion
Wirtgen W 240 CR(i) or W 380 CR(i) cold recycler
Vögele paver, for example a SUPER 2100-3(i)
Hamm tandem roller or Hamm compactor
Hamm pneumatic-tyre roller

Cold recycling technology from Wirtgen

Worn or damaged asphalt layers can be renewed in a number of different ways with cold recycling technology from Wirtgen. In a train with other equipment, the tracked mobile cold recyclers from Wirtgen rehabilitate damaged traffic infrastructure in-place – i.e. on the spot – in a process known as cold in-place recycling (in short, CIR). In addition to this method, Wirtgen also offers an in-plant process with the KMA 240(i) cold recycling mixing plant.

Learn more about the KMA 240(i)

Wirtgen also brings the benefits of extensive cold recycling expertise to the construction site

In the in-place process, the milling and mixing rotor of the Wirtgen cold recycler granulates the asphalt layers to be rehabilitated. The milled material and pre-spread cement are then mixed together with foamed bitumen and water in the variable mixing chamber of the W 240 CR. In the next step, the fresh cold recycling mix produced is paved in-place. The paving is carried out either with a Vögele paving screed mounted on the Wirtgen cold recycler (cold recycling with integrated paving screed), or by a Vögele paver following behind that is fed directly with the cold recycling mix from the discharge conveyor of the W 240 CR or W 380 CR (cold recycling with rear loading). Finally, Hamm rollers carry out the final compaction of the cold recycling layer. In the long-term, the layer produced in this way withstands sustained heavy traffic.

Tolles Produkt

Fleet expansion with a Wirtgen W 240 CR cold recycler

The engineering and construction company Tangshan Dacheng Road & Bridge Co., Ltd. recently realised a prestigious project with its newest machine, a Wirtgen W 240 CR cold recycler: the rehabilitation of the Yingxiang Road in Tangshan City in the Hebei Province of China. The company already owns and operates numerous other machines from the Wirtgen Group. The company’s fleet also includes a W 380 CR, the currently most efficient Wirtgen cold recycler.

The Wirtgen W 240 CR cold recycler mills off the asphalt with the down-cut method, granulates it and mixes the resulting material with the pre-spread cement, water and foamed bitumen.

Wirtgen technology – cold recycling with foamed bitumen: structurally advantageous

Cold recycling with foamed bitumen is a winning combination when it comes to road rehabilitation. Whether as in-place rehabilitation with a CR or WR series cold recycler, or with a surface layer mix produced off-site in a Wirtgen cold mixing plant: Foamed bitumen is the essential ingredient for an extremely durable bitumen stabilised mix (BSM) and greater sustainability in road construction.

Cold recycling with foamed bitumen conserves valuable resources, reduces CO₂ emissions and, as the entire reclaimed asphalt pavement is recycled, also cuts construction costs. Around the world, more and more players in the road construction industry are recognising the clear benefits of using this technology.

Rehabilitation with the cold recycling paving train

In Tangshan City, a metropolis with a population of 7.7 million, the Yingxiang Road, one of the most important road links between several communities in the city’s Guve district, was earmarked for rehabilitation. The road has an overall length of 4.8 km, and serves as a bypass for China National Highway 205. The original layer structure consisted of a 20 cm cement-treated crushed stone base course and a 4 cm surface course.

A part of the existing base course was milled of together with the entire surface course and mixed with thecement and foamed bitumen as binding agents in the mixing chamber of the Wirtgen W 240 CR cold recycler to produce a new, 10 cm, cold recycling layer that was followed by a new, conventionally mixed surface course with a thickness of 5 cm. The ideal ‘recipe’ for the cold recycling mix was determined beforehand by laboratory analysis. For this purpose, Wirtgen offers the WLB 10 S mobile laboratory unit, which enables the precise definition of the quality of the foamed bitumen.

The complete recycling of the existing road construction materials and the minimisation of site logistics make the cold recycling method environmentally friendly and particularly cost-efficient.

Lateral pre-milling extends the working width of the W 240 CR

The project brief was the rehabilitation of the Yingxiang Road over a width of 6.5 m. The 2.35 m milling drum of the Wirtgen W 240 CR cold recycler is actually not wide enough to enable the completion of the job in two passes. This was, however, made possible by the addition of a Wirtgen W 100 H small milling machine to the paving train. This machine drove ahead of the cold recycling paving train and milled off a strip at the side of the road to the required depth of around 15 cm. The W 100 H deposited this additionally milled material on the road surface so that the Wirtgen W 240 CR cold recycler was able to take it up and incorporate it in the mixing process.

On the construction site in Tangshan, a Wirtgen W 100 H small milling machine milled off the part of the road surface that could not be milled with the maximum possible milling width of the W 240 CR. This solution enabled the extension of the working width of the paving train.

Transfer of the mix to the SUPER 2100-3

After the transfer of the cold recycling mix, the Vögele SUPER 2100-3 paver was able to realise a working width of around 3.25 m. Two passes thus enabled the rehabilitation of the road surface to its full width of 6.5 m.

After milling and mixing in the binding agents, the Wirtgen W 240 CR cold recycler transfers the mix directly to the material hopper of the Vögele SUPER 2100-3 paver behind it. The Vögele SUPER 2100-3 paved the cold recycling mix to a width of 3.25 m.

The compact Wirtgen W 240 CR(i) cold recycler: ideal for a wide range of applications

Cold in-place recycling (CIR) and full-depth reclamation (FDR): Wirtgen CRseries machines are used as part of a paving train for cost-effective cold in-place recycling of road surfaces in a single pass by adding cement, bitumen emulsion or foamed bitumen to milled material at a mixing capacity of up to 800 t/h.

The W 240 CR(i) compact cold recycler is ideal for uncomplicated rehabilitation of road surfaces with an integrated paving screed or by feeding the cold recycled mix directly to the hopper of a Vögele paver. The actual working width is 2.35 m, but can be extended by pre-milling strips along the side of the road.

In contrast to the larger Wirtgen cold recycler, the W 380 CR (working width 3.8 m), the W 240 CR offers the benefits of easier transportation and a wider range of potential applications, up to and including projects in urban environments.