ROADS AND BRIDGES
Mobicast, Terraforce licensee in the Garden Route area, suggested
the Terracrete paving block, a permeable and interlocking
eco-surface paver that can be laid in different patterns and may
be used with or without ground anchors for the lining of riverbanks,
roads and other areas subjects to soil erosion.
Finding a versatile solution
The blocks where installed to form a two-wheel jeep track as an erosion
control and maintenance measure for existing sand tracks. “We have a
network of maintenance jeep tracks that give us access to the different
sections of the reserve. The substrate is mostly deep dune sand, making
it inadequate to surface with normal paving. Putting down a road base
foundation and or compacting have been proven to be very costly due to
the nature of the substrate,” says Jean du Plessis, conservation manager,
Geelkrans Cluster & Stilbaai Marine Protected Area (MPA).
“Investigating alternative solutions produced the principle of putting
down a ‘hard’ surface that is permeable for water and vegetation.
The idea is also that the surfacing material should then be able to move
with the substrate while keeping its shape and integrity. We decided to
use the Terracrete blocks because of their permeable nature, minimal
impact on the environment and cost-effectiveness. “
Low impact, low cost
The blocks are relatively easy to work with, compared to other methods
that involve more sophisticated machinery and labour. “We do get
breaking of about 2% of the blocks during handling as the transport of
the blocks to the target areas does require a minimum of two loading/
offloading processes due to the nature of the terrain, but on the whole
the process is straightforward and causes very little disturbance in the
reserve, which is what we were looking for. Another benefit is that the
blocks, if they do break, are easy to replace, making maintenance of the
tracks quick and easy,” says Du Plessis.
Construction commenced in March 2013 and is still ongoing. The
tracks are installed in stages of 250 m each, with 7 000 blocks already
laid down. To rehabilitate any destabilisation that did occur during
construction
Carpobrotus edulis
(sour fig) were planted on the verges
of the jeep track.
HARDY AND
VERSATILE
The client, Cape Nature was looking for a
permanent, yet flexible solution for jeep tracks
on deep sandy substrates at Geelkrans Nature
Reserve, Stillbaai, without the associated footprint
impacts of commonly used hard structures such
as asphalt or paving.
>
CONSTRUCTION WORLD
JUNE
2014
