SUSTAINABILITY
RECYCLED ASPHALT:
EFFICIENT, EFFECTIVE, ECONOMICAL
By Robyn Grimsley
As focus shifts towards using more recycled material, the need for better recycling technologies
becomes more pressing. So, too, does the need for more effective, efficient, and economical
methods of processing secondary materials, as well as better ways of dealing with reclaimed
asphalt pavement (RAP).
W
hile new demands in
the paving business are
resulting in the evolution
of asphalt plants, at the
same time, companies and governments
are on the lookout for ways to incorporate
more recycled asphalt into road building
and rehabilitation projects. This is not only
to preserve natural resources, but also to
optimise production costs thanks to the
aggregate and bitumen savings resulting from
the use of modern recycling techniques.
The availability of the aggregates and
bitumen used in asphalt production is
steadily decreasing as more is mined, and
this results in higher costs for the quarrying
of aggregates, as well as increased costs
in bitumen production. Additionally,
construction and demolition (C&D) waste is
up to 22% by mass in landfills across South
Africa. C&D waste recycling is a growing
industry, particularly when landfill space is
limited and the costs of virgin material can
be high.
The drive to increase the amount of
recycled materials used in construction and
road building, coupled with the requirement
to decrease CO 2 emissions, has led to an
increasing industry focus on recycled or
reclaimed asphalt paving (RAP). Recycling
is the most environmentally friendly
method of dealing with C&D waste, ahead of
landfill and incineration (Ortiz et al., 2010,
in Ulubeyli et al., 2017). In addition to the
environmental benefits of reusing materials,
there are significant cost-saving implications,
primarily due to the reduction of material
costs, including asphalt binder, energy costs,
and total job costs, including transportation.
Making use of granulators — machines that
gently separate reclaimed asphalt into its
individual components without destroying the
original grain structure — in combination with
an asphalt mixing plant can create new roads
comprising over 90% recycled materials.
Asphalt pavement is 100% recyclable and
reusable. RAP is added to hot mix asphalt
in varying quantities, depending on the
QUARRY SA | NOVEMBER 2017 _ 27