Addition of binding agents

Precise metering system

Simply keying in the specified parameters once is not enough to achieve high-quality mixing results. They need to be maintained at their preselected values for the entire duration of the stabilizing or recycling operation. The WR has all it takes to meet these requirements: parameters are entered quickly and conveniently via a small number of controls in the left-hand arm console and via the control screen. The menus are structured clearly and logically, enabling the individual pages to be called up quickly. Large, readily comprehensible displays keep the operator fully informed of current parameters during the operation and, if need be, he can adjust the relevant parameters quickly and easily.

Microprocessor-controlled flow meters govern the addition of water, bitumen emulsion or foamed bitumen. The binders are added in accordance with the previously specified parameters, such as working width, working depth, material density and machine advance rate. The injection bars are fitted with up to sixteen spray nozzles each which can be switched on or off separately at any time during the process to adjust the spraying width.

Foamed bitumen
A binding agent offering lots of potential.


Strict compliance with the specified binder amounts to be added is of paramount importance for high-quality stabilizing and recycling operations. The WR is fully equipped to meet these requirements: robust, microprocessor-controlled injection systems can be relied on to precisely govern the addition of water, bitumen emulsion or foamed bitumen. Several injection bars can be installed and several additives injected simultaneously in accordance with application requirements. In addition, a special quick-mounting feature enables the injection bars to be installed or removed quickly and effortlessly.

Tanker trucks driving ahead deliver water and bitumen emulsion to the injection bars via feed hoses connected to the recycler. The microprocessor-controlled injection bars for water and bitumen emulsion are of identical design and can be used for both substances to comply with application requirements. Bitumen emulsion improves the flexibility of the new base layer and reduces cracking. The optimum moisture content is achieved by simultaneously adding water to the process.

For base layers of exceptionally high quality, the WR produces foamed bitumen in up to sixteen separate expansion chambers by injecting small amounts of water and compressed air into hot bitumen which has a temperature of approx. 180°C. The hot bitumen then foams abruptly, expanding to many times its original volume. In this state, the foamed bitumen disperses very evenly in the mineral aggregate mix to be recycled. All components carrying hot bitumen are heated and kept at operating temperature, thus dispensing with the need to flush the system. All benefits considered, foamed bitumen is an exceedingly cost-efficient binder. A test nozzle offers ready access for continuous monitoring of the foam quality during the recycling operation.

Self-cleaning feature comes as standard

Movable tappets automatically remove any binder build-ups occurring at the nozzle outlets during the recycling operation. Regular self-cleaning of the spray nozzles via the tappets ensures precise metering across the entire working width. Cleaning of the nozzles is not only performed automatically at fixed time intervals but can also be conveniently activated manually via the screen whenever necessary. Raising the revolving rotor to maximum height manually at the same time enables build-ups of encrusted material at the nozzle outlets to be removed.

Self-cleaning feature: the tappets remove any material build-ups at the nozzle outlets.

Self-cleaning feature: the tappets remove any material build-ups at the nozzle outlets.

Individual tappets clean the up to sixteen nozzles at predetermined intervals.

Individual tappets clean the up to sixteen nozzles at predetermined intervals.

Integrated binder spreader

The “S-Pack” (Spreader-Pack), which can be integrated in the WR 240, WR 240i or WR 250 as an optional feature, is the ideal candidate for the dustless addition of binding agents in cold recycling or soil stabilization. Lime or cement is spread right in front of the milling and mixing rotor in a microprocessor-controlled operation. “S-Pack” is synonymous with the reliable and dustless processing of binders especially on motorways, in industrial estates specifying strict emission requirements, residential areas or nature reserves.

The “S-Pack” spreader is loaded to capacity in less than five minutes. A standard 27-tonne silo transporter is emptied within two hours. The spreading process is controlled and monitored intuitively via the integrated control screen. The outstanding all-terrain mobility of the WR model series now allows binders to be spread safely and precisely even on insufficiently stable ground.

Dustless, highly precise spreading of binders regardless of weather conditions.

  1. Metering cells

    Microprocessor-controlled metering cells ensure precise volumetric metering. The spreading quantity is controlled via weighing plates.

  2. Filling port with shut-off valve

    The readily accessible filling port enables easy filling of the binder container. The vent air filter system is activated automatically upon opening of the shut-off valve.

  3. Conveying unit

    The conveying unit ensures continuous transport of the binder to the cross-feeding auger and complete drainage of the container.

  4. Cross-feeding auger

    The divided cross-feeding auger ensures uniform discharge of the binder across the full working width.

  5. Dust protection

    The dual rubber cloth guarantees effective dust protection, keeping even large spreading quantities right on track.

  6. Binder container

    The binder container has a gross volume of 5.5 m³.

  7. Inspection port

    The inspection port offers ideal access for inspection of the binder container.

  8. Vent air filter system

    Vent air filters with automatic cleaning feature guarantee quick, dustless filling.

  9. Closing panels

    The spreading width (max. 2.4 m) can be varied in increments by selecting or deselecting one or more of the three closing panels of 80 cm width each.

  10. Sensors

    The filling level of the binder container is measured via sensors installed at different positions and indicated on the control screen, which is also used to calibrate the sensors for different types of binding agents.

Maximum customer benefit

  • Dustless, precise spreading of binders regardless of weather conditions.
  • Compliance with strict emission standards wherever the development of dust must be avoided.
  • Operation of the unit fully integrated into the control screen.
  • Low labour, machine and transport costs.
  • Traffic, in particular on motorways, is not impaired by windblown pollution.
  • Precise binder discharge even on insufficiently stable ground.

Market-leading and cutting-edge products for the Road and Mineral Technologies business sectors are constructed at the WIRTGEN brand headquarters in Windhagen, Rhineland-Palatinate. With its innovative, high-performance and cost-efficient products and technologies for cold milling, soil stabilization, hot and cold recycling, concrete paving and surface mining, WIRTGEN leads the world market in road construction and repair, as well as in mining natural rock and pay minerals.