Wirtgen World Leader in Cold Asphalt Recycling Technology
13 March 2017
Wirtgen Group is the world leader in advanced technologies that conserve resources through reuse and recycling of construction materials. With 10 different models of plants and machines available, Wirtgen has the right equipment for productive and profitable asphalt and concrete construction materials recycling, ranging from wheeled and tracked cold recyclers and the new mobile cold recycling mixing plant KMA 220i, to ancillary equipment such as the new laboratory compactor WLV 1. At Conexpo-Con/Agg 2017 in Las Vegas, Wirtgen is exhibiting the full-lane 3800 CR cold recycler.
Roads that are subject to heavy and continual loads frequently show signs of damage in the subgrade. To fix, the entire structure of the road must be reconstructed. Other roads exhibit surface damage that can be renewed without delving into the subgrade. Either way, in the cold recycling process, 100 percent of the reclaimed material can be reused and cost-effectively treated, making cold recycling both an economical and an environmentally friendly option. As a pioneer of cold recycling technology, Wirtgen has played a key role in shaping these processes over the last 30 years, and has systematically advanced the range of cold recycling products.
Cold recycling in-place (CIR)
Wheeled cold recyclers of the WR series
Wirtgen offers three wheeled recyclers: the WR 200i, WR 200 XLi, WR 240i and WR 250 models. Equipped with a powerful milling and mixing rotor as well as cutting-edge injection systems, they mill and granulate asphalt pavements, inject binding agents and water in precisely metered quantities, and mix it all in a single in-place operation.
Tracked cold recyclers and a new process
Wirtgen also offers two tracked machines: the 2200 CR and 3800 CR cold recyclers with working widths of 7 ft., 3 in. and 12 ft., 6 in. (2,2 m and 3,8 m) respectively. Like the models of the WR series, they process asphalt roads on the spot. Both of them, however, can also be fitted with an integrated, infinitely adjustable Vögele paving screed with tamper and spreader auger in order to precompact the freshly recycled asphalt true to line and level, bypassing the need to use a paver to distribute recycled material.
In addition to recycling with the conventional up-cut method, the two models can also perform what is known as down-cut milling, a recent development by Wirtgen in its drive to optimize the cold recycling process. In this case, the recycled material is rear-loaded directly onto a paver, which immediately paves and compacts it. Rollers subsequently carry out final compaction. The down-cut process allows the particle size to be precisely controlled during material processing, especially when milling very old and brittle asphalt roads.
Wirtgen ancillary equipment enhances quality in construction projects
An extensive analysis of the entire road pavement – as well as comprehensive mix design testing – are essential if the quality of the paving is to be determined in advance. Wirtgen offers a range of supporting equipment, developed specifically for this purpose, allowing 1:1 simulation of the cold recycling process in the road construction laboratory.
Laboratory compactor WLV 1
The Wirtgen laboratory compactor WLV 1 is designed for the laboratory production of cold recycling mix test specimens. Specially developed for cold recycling applications, the compaction process allows the production of large test specimens with a diameter of 6 in. x 12 in. (150 mm x 300 mm) for the purposes of a triaxial test. Furthermore, test specimens with a diameter of 6 in. x 3.74 in. (150 mm x 95 mm) can be produced. These are used to measure the indirect tensile strength of the cold recycling mixture. In combination with a test system specific to the WLV 1, information is obtained from the specimens that can then be used to determine the required material properties for dimensioning the road pavement.
Laboratory foamed bitumen plant WLB 10 S
Foamed asphalt is increasingly being used as a binding agent in economical cold recycling. Preliminary testing with the WLB 10 S mobile laboratory unit allows the quality of the foamed bitumen to be defined precisely in the lab even before construction work begins. The system is very easy to use, allowing parameters such as water quantity, pressure and temperature to be varied quickly.
Twin-shaft compulsory mixer WLM 30
The optimum mix composition can be defined in combination with the twin-shaft compulsory mixer WLM 30. In large batches of 66 lbs. (30 kg), this powerful mixer generates reliably homogeneous specimen mixtures with lime, cement, asphalt emulsion or foamed asphalt. When combined with the laboratory foamed bitumen plant WLB 10 S, the foamed asphalt or bitumen is added directly into the continuous mixing process.
Cold recycling in-plant
Wirtgen cold recycling mixing plant KMA 220i
The mobile concept of the Wirtgen KMA 220i offers easy setup and efficient mix production close to the construction site. All of the reclaimed asphalt can be reused and processed. The mixing plant is environmentally friendly in every respect: The source materials for mix production do not need to be dried or heated, saving a great deal of energy and costs. Time-consuming trucking between the mix production site and the job site is reduced to a minimum. This has a huge positive impact on fuel costs while at the same time drastically cutting CO2 emissions.