Uncontrolled cracking of materials treated with hydraulic binders leads to pavement deterioration
that can jeopardize pavement durability and user safety. A technique known to be cost-effective
and prevent accidents, which is applied during the laying of materials treated with hydraulic
binders, can directly influence the cracking process inherent in these materials. Eurovia, a pioneer
in the field, has developed two pre-cracking processes: Craft® and Olivia.
2. Key
Benefits
Simple, cost effective processes
No reduction in application speed
Two solutions to meet specific worksite
requirements
Perfectly controlled cracking
key
figures
Uncontrolled cracking of materials treated with hydraulic binders leads to pavement deterioration
that can jeopardize pavement durability and user safety. A technique known to be cost-effective
and prevent accidents, which is applied during the laying of materials treated with hydraulic
binders, can directly influence the cracking process inherent in these materials. Eurovia, a pioneer
in the field, has developed two pre-cracking processes: Craft®
and Olivia.
CRAFT®
- OLIVIA
PRE-CRACKING
Up to 5m width achievable
with the Craft®
and Olivia
equipment
30-year track record
for the two patented processes
3. verstility COMBINED
WITH PERFORMANCE
Pre-cracking is a preventive process that can be
applied to all roadworks materials treated with
hydraulic binder: gravel and sand treated with
cement, slag and hydraulic binder, compacted
concrete, optimised cement-bound aggregates.
For the national road network, the Sétra/LCPC
catalogue of standard structures requires pre-
cracking of materials treated with hydraulic binder
used in heavily trafficked pavement base courses
and Class 4 cement-bound gravel.
For lighter traffic and other classes of cement-
bound aggregate, pre-cracking remains “highly
recommended”.
With Craft®
and Olivia, Eurovia offers simple,
effective and cost-effective processes.
easy
application
Pre-cracking consists in creating transverse
discontinuities in the course that is being laid over at
least 1/3 of its thickness, in most cases at intervals of
4m. These discontinuities are later transformed into
thin, regular, straight cracks at controlled intervals;
they require no particular maintenance.
The technique offers:
excellent load transfer due to the intermeshing of
the materials
reduction or elimination of the risk of reflective
cracking in bituminous surface courses.
The Craft®
and Olivia processes both use special
compact self-propelled equipment that can be
readily included in the laying train, ahead of final
trimming and compaction, without disrupting the
worksite or reducing productivity.
cracks
SHOULD BE CONTROLLED!
4. CRAFT®
at a glance
The Craft®
process consists in creating temporary
grooves in the material laid and in projecting a
bitumen emulsion film into them.
The cationic emulsion plays a dual role:
its low-pH aqueous phase creates a zone of lower
strength that promotes local cracking
its bituminous phase creates a permanent
discontinuity and reduces the sensitivity of the
material to water and abrasion.
The pre-cracking device is installed at the front of a
front-end loader. It is made up of an articulated arm
in the shape of a compass with a tool attached to its
end that opens the groove, injects the emulsion and
closes the groove.
The Craft®
equipment operates at widths of up to
5m. and maximum depths of 0.30m, which generally
corresponds to pre-cracking of between 2/3 and
the entirety of the thickness of the material applied.
OLIVIAat a glance
Olivia consists in vertically inserting a thin sheet
of polyethylene into the treated layer. When the
material shrinks, the crack appears at the place
where the plastic film was introduced.
The sheet is very thin (40 to 80microns) and can
deform during compaction, ensuring excellent
meshing of materials.
The equipment was devised, designed and built by
Eurovia. It is made up of a telescopic beam mounted
on an independent forklift truck under which a tool
moves to create a groove and position the plastic
film a few centimetres below the surface.
The width of the plastic ribbon is in most cases
equal to one third of the thickness of the layer
applied.
The Olivia equipment works in widths of 3 to 5m.
Craft®
was developed by Eurovia in conjunction with the
Ponts et Chaussées Laboratory network. The process is
patented and covered by a French Technical Opinion No. 141
of February 2004.
Oliviais also a patented process.
Craft®
is registered trademarks.
two equally demanding
solutions
TECHNICAL DEPARTMENT
18, place de l’Europe - 92565 Rueil-Malmaison cedex
Tel. : 33 (0)1 47 16 38 00 - Fax : 33 (0)1 47 16 38 01
www.eurovia.com
technique@eurovia.com
-February2014-photoscredit:photolibraryEurovia