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Laboratory-scale foamed bitumen plant WLB 10 foamed bitumen plant WLB 10 S

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  • Preliminary testing for determining the mix quality

    Laboratory-scale foamed bitumen plant WLB 10 S

  • What is foamed bitumen?

    For high-quality base layers from cold mixes

    Foamed bitumen is produced from standard grade

    bitumen used in asphalt road construction. When

    heated and foamed, bitumen permits the economical

    production of high-quality base layers from cold mixes.

    Foamed bitumen is produced by injecting small quantities

    of water and compressed air into hot bitumen. The water

    evaporates, causing the bitumen to foam abruptly and

    expand to around 15 to 20 times its original volume.

    The quality of foamed bitumen is primarily described in

    terms of the parameters “expansion ratio” and “half-life”.

    For the larger its expansion and the higher its half-life, the

    better suited to processing the foamed bitumen will be.

    Hot bitumen

    Water Air

    Foamed bitumen

    Expansion chamber with foam nozzle

  • 2 //3

    Innovative and economical

    The foaming process takes place in expansion cham-

    bers where water and air are injected into hot bitumen

    (160°C to 180°C) at a pressure of approx. 5 bar.

    The foamed bitumen sprayed from the nozzle at the

    expansion chamber is suitable for direct mixing with the

    mineral aggregate mixture.

    Compared to other binding agents, foamed bitumen

    offers the advantage of reduced transport and material


    Bitumen used for the production of foamed bitumen is

    readily available in all parts of the world.

    Small quantities of water cause an abrupt increase in the volume of the hot bitumen

    Development of half-life and expansion ratio for

    determining the water content

    Foamed bitumen nozzle: from the expansion chamber, foamed bitumen is injected into the mixer for the production of test specimens

    Expansion ratio Half-life








    e (s


    Water content (% by weight)


















    20,5 1 1,5 2 2,5 3 3,5 4 4,5 5 5,5

  • The WLB 10 S determines the optimum foamed bitumen quality

    One-to-one simulation of the cold recycling process in the lab

    Foamed bitumen is used to an ever-increasing

    degree as a binding agent in economical cold

    recycling. Preliminary testing with the mobile WLB 10 S

    laboratory-scale plant enables the foamed bitumen qual-

    ity to be precisely determined in the lab even prior to the

    start of construction. Extremely simple handling permits

    different parameters, such as water quantity, pressure and

    temperature, to be varied quickly, and different types of

    foamed bitumen to be produced within a short period of

    time. Based on the results achieved, the WLM 30 labora-

    tory-scale mixer can then be used to determine the mix

    proportion and to define the optimum bitumen foam for

    production of the test specimens.

  • 4 //5

    True ease of operation

    The integrated air compressor (optional) enables the

    plant to be operated even in those locations where

    there is no external supply of compressed air.

    The compact plant guarantees simple and ergonomical

    handling and operation.

    Comprehensive safety functions, such as compressed

    air and temperature monitoring, permit the foamed

    bitumen to be produced under ideal conditions.

    The plant is also intended for testing the suitability of

    mixes by adding cement or lime in combination with

    foamed bitumen.

    Controlled electrically: the plant offers maximum accuracy, for example, by

    calibrating the bitumen flow

    The clearly and logically arranged control panel permits easy setting and monitoring of key parameters

    Precise process water settings enable the ideal foamed bitumen

    quality to be determined

  • WLM 30 laboratory-scale mixer for the production of cold mixes

    A perfect match for the WLB 10 S

    Direct injection of the foamed bitumen into the mix-

    ing chamber of the WLM 30 laboratory-scale mixer

    enables mixes to be processed to specification and test

    specimens to be produced. The twin-shaft compulsory

    mixer is not only ideally tailored to the laboratory-scale

    plant in terms of performance and design, however, but

    is also connected to the plant’s power supply. The high

    mixing intensity matches that of continuous mixers used

    on the construction site. The WLM 30 has a capacity of

    approx. 30 kg, and additionally offers variable settings

    for speed and mixing time. The mixing chamber is simply

    pivoted downwards about 180° and the cover opened to

    allow discharge of the mix. And what’s more: when used

    separately, the WLM 30 is suitable for most diverse mix


    Mixes every bit as homogeneous as on the job site

    The powerful mixer (optional) with heavy-duty blades produces most diverse cold mixes

    The two units are positioned relative to one another safely

    by means of fixation points

  • Reliability even prior to the start of construction

    6 //7

    Maximum reliability for your cold

    recycling project

    Preliminary testing includes the procurement of

    raw materials, determination of the mix formula,

    and suitability testing on the test specimens.

    Using the WLB 10 S and WLM 30 laboratory-scale

    plants permits the final pavement design to be

    determined in advance.

    The two machines ensure an accurate analysis of

    mixes produced from granulated asphalt material,

    virgin materials or a mixture of both.

    Our broad, innovative product portfolio enables us

    to rehabilitate roads with maximum reliability and

    economic efficiency.

    Quality testing by means of the indirect tensile strength test

    Ideal pavement properties are ensured by precisely determining

    the mix proportion

    Specimens produced from fresh mix for suitability testing

  • Wirtgen GmbHReinhard-Wirtgen-Str. 2 · 53578 Windhagen · Germany

    Phone: +49 (0) 26 45 / 131-0 · Fax: +49 (0) 26 45 / 131-242Internet: · E-Mail: [email protected]

    Illustrations are non-binding and may include customized fittings. Subject to technical changes. Performance data depend on operational conditions. No. 54-12 EN-03/09 © by Wirtgen GmbH 2009. Printed in Germany