consistently been cheaper since 1994 — a
scenario replicated in South Africa.
However, Mayor Buck Clark was a
diligent official who wanted to make
sure the city council was doing the right
thing and insisted on getting input from
representatives of the Iowa Concrete Paving
Association (ICPA) and the Asphalt Paving
Association of Iowa, before spending the
roughly USD4-million in reconstruction
projects, which involved completely tearing
up existing failed streets and replacing the
sewers, curbs and gutters, and surface.
The city typically also spends an equal
amount each year on an asphalt overlay
programme, which involves extending the
life of a crumbling street by putting a few
inches of asphalt on the top.
According to the WCF Courier, Clark
was reported as saying: “I was trying to
get this done when I was [a councilman]
because I never quite understood why we
never got bids from concrete contractors. I
want to confirm that what we are doing in
Waterloo in reconstructing our streets was
the right thing.”
The specifications called for a 6-inch
(150mm) concrete thickness on a
residential street while asphalt must be
7.5-inches (190mm) thick.
The argument of the ICPA was that
cities do not conduct a lifecycle cost
analysis when determining which bid
is better in the long run. “Our industry
believes we’re providing a benefit with
durability,” John Cunningham of the ICPA
was reported as saying.
While the city may design a street to last
for 30 years, a concrete street will need little
maintenance during that period, while an
asphalt street will need a major overlay in
15 years, he said. The Iowa Department of
Transportation often factors in a 20-year
resurfacing for asphalt on a 40-year
street project.
“That mid-life resurfacing is significant,”
Cunningham said. The Waterloo agency
uses a lifecycle cost analysis that shows
“asphalt pavement is projected to require
major rehabilitation in approximately half
the time as the concrete pavement”. But
it said that’s just one factor in the overall
decisions on pavement types for state
projects. Others include availability of
local materials and a desire to keep both
industries viable in the state’s economy.
WordPress.com
BENEFICIATION
South Africa’s asphalt roads look like this after a few rainy seasons.
While less costly to maintain, concrete is
typically 10% higher in initial construction
costs, and asphalt can be installed more
quickly with less traffic disruption.
South African pavements
Johan van Wyk, director of the Southern
African Ready-mix Association (Sarma),
says that lifecycle cost analysis is the only
way to compare the costs. “Some of our
concrete roads have been in existence for
many years — and over that lifecycle, they
cost much less than what asphalt roads
do, but if one looks at a short timeline of
only four years, then asphalt is cheaper.
Unfortunately, politicians have a short-term
time horizon which extends no further
than the next election, and so the inevitable
potholes will only manifest during his
successor’s administration.
“We’re not in competition with asphalt
regarding roads. Our argument is to ensure
the country can afford more roads and
have the right surface in the right areas.
Concrete is an obvious choice for heavy-
density freeways and suburban traffic
circles. This would reduce maintenance
and make more money available for more
roads,” argues Van Wyk. “If you put the
wrong material on road surfaces, you will
have fewer roads. Concrete itself, done
properly, has a long lifespan.”
Hard sell to government
Perrie says that TCI has been trying “for 50
years” to promote concrete roads in South
Africa. The efforts have not been entirely
fruitless as there have been some concrete
roads; either entire freeways, lanes that
take heavy-load rucks, or heavy-traffic
intersections — but in the main, he says,
“They have been a hard sell to government
officials, particularly in the provinces
and municipalities where short-termism
predominates.”
“Government is under pressure to
deliver services and doesn’t want to look
further down the line. In the US and EU,
such decisions are made by technocrats
— and the same used to be the case in
South Africa, but today they are made by
politicians.” While engineers are involved
in the decision-making, their views are
side-checked by politicians from a short-
term budgetary point of view.
He suggests a government official
would rather be seen as delivering more
kilometres of road in terms of service
delivery statistics, than to construct longer-
lasting ones. “After all, when the asphalt
road develops potholes, he may no longer
be in the same office.” Apolitical, the TCI
limits its lobbying to the cost-benefit merits
of concrete.
“Where we have been successful in
promoting concrete roads is on heavy-
traffic roads, particularly in areas of
KwaZulu-Natal where weather conditions
cause deterioration and more frequent
maintenance,” says Perrie.
Hybrid concepts
TCI has evolved its lobbying from being
a ‘black or white’ issue, to presenting
QUARRY SA | SEPTEMBER/OCTOBER 2018 _ 27