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,
better suited to processing the foamed bitumen will be.
Expansion chamber with foam nozzle
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
Expansion ratio Half-life
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
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.
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
Controlled electrically: the plant offers maximum accuracy, for
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
quality to be determined
WLM 30 laboratory-scale mixer for the production of cold
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
Maximum reliability for your cold
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
Quality testing by means of the indirect tensile strength
Ideal pavement properties are ensured by precisely
the mix proportion
Specimens produced from fresh mix for suitability testing
Wirtgen GmbHReinhard-Wirtgen-Str. 2 · 53578 Windhagen ·
Phone: +49 (0) 26 45 / 131-0 · Fax: +49 (0) 26 45 /
131-242Internet: www.wirtgen.com · 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