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CONSTRUCTION WORLD
MAY
2016
PROJECTS AND CONTRACTS
This project involves continuing
construction of an access road to
the open-cast pit, where mining
excavation is taking place.
“A major challenge was the formation
of a durable road structure, with sufficient
bearing capacity to withstand required loads,
including dump trucks carrying in excess
of 250 t of ore per trip,” says Chris Powell,
Fibertex South Africa – manufacturers of
geosynthetic products. “Continuous heavy
wear and regular rainfall in this region
necessitated a robust road formation, with
prolonged service life and minimal mainte-
nance requirements.”
Fibertex F750M Polypropylene nonwoven
geotextile was introduced as a basal
separator to prevent aggregate grade mixing,
with no risk of contamination of the aggre-
gate base. In road construction, migration of
the various layers reduces the load bearing
capacity of the road and must be prevented.
The solution
The Fibertex nonwoven geotextile’s porous
structure prevents the migration of weak
subsoils into the quality engineered fill and
also inhibits the loss of quality aggregate
into the weak subgrade below. In this
process the geotextile also provides
stability to the base layers.
The ‘tension membrane effect’ provides
the required compaction of the road aggre-
gates and thus increases the bearing capacity
of the road to withstand continuous heavy
traffic loads.
Geotextiles, with excellent hydraulic filter
properties, have sufficient permeability to
allow free movement of water.
This will provide long term stability of the
foundation layers and ensure an extended life
of the new road.
Another advantage of using geotextiles
in this project is the significant reduction of
fill material required during construction.
Because of the lack of suitable construc-
tion materials in remote African locations,
construction aggregates often have to
be transported, at a huge cost, over long
distances. By reducing the amount of engi-
neered fill required, the installation is simpli-
fied and time and cost savings are achieved.
Fibertex non-woven geotextiles are
engineered to have high mechanical stability,
not only for in-field performance, but also
for possible damage that occurs during the
installation process.
Geotextile mechanical stability is
achieved by having a high elongation and
high tensile strength per weight, to resist
failing under load.
During construction, when sharp heavy
rocks are dumped directly onto the geotex-
tile, or when heavy construction traffic forces
the geotextile into the subsoil, the geotextile
will strain or elongate, while maintaining its
mechanical integrity.
Other critical durability features include
the geotextile’s stability over a wide pH range
(3-12) and its resistance to fungal attack
and biodegradation – an inherent quality of
the Polypropylene polymer the geotextile is
produced from.
In applications where the geotextile
will be left exposed for prolonged periods,
UV inhibitors are added as part of the
polymer extrusion process to give long term
UV stability.
An extensive range of geotextiles is manu-
factured at the Fibertex manufacturing facility
MINE ROAD
construction
Fibertex South Africa has supplied high
volumes of heavy grade nonwoven needle
punched geotextiles to be used in ongoing
road constructions at a major gold mine in
Ghana’s Akyem mining region.
in Hammarsdale, KwaZulu-Natal, according
to stringent international quality, safety and
environmental specifications.
This involves line testing for a consistent
high quality product and QC testing to
ensure all nonwoven products meet every
customer’s requirements.
The local operation – which forms part
of a global organisation, with its head office
in Denmark – incorporates a combination
of carding; needle punching and thermal
bonding processes, using the latest tech-
nology. All processes are automated and
product quality is controlled by a central QA
system. Concern for the environment is crit-
ical at Fibertex and no chemical binders are
used in the product or production process.
Geosynthetic range
The Fibertex geosynthetics range encom-
passes nonwoven and woven geotextiles,
gabions and mattresses, drainage pipes
and fittings and erosion control and cellular
confinement solutions.
The company also supplies soil rein-
forcing products, including geogrids and
geocells, as well as geosynthetic clay
liners as part of composite lining systems
in modern landfills.
Fibertex industrial nonwoven fabric
products are manufactured for use in a
diverse range of industries, including
automotive, filtration, furniture and
flooring applications.
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A major challenge was the formation of a durable
road structure, with sufficient bearing capacity
to withstand required loads, including dump
trucks carrying in excess of 250 t of ore per trip.