Concrete cancer is a term used to
describe the problem of concrete spalling and cracking caused by rebar
corrosion in buildings and concrete structures.
When the steel reinforcing within a concrete slab starts to rust, the
steel rust can expand up to 7 times its original size, which causes concrete to
be displaced and become flakey. The
process intensifies as the steel pushes the concrete away (referred to as
concrete spalling), and more water comes into contact with the steel, which compounds
the problem.
Beside flaking and cracking, other
signs of spalling concrete include rust stains that appear to be coming from
within the concrete, leaks, and bubbling.
Often the problem is blamed on weathering or aging concrete, but the
problem can be dangerous. Spalling can
cause chucks of concrete to separate from structures such as buildings and
bridges and present a real hazard to pedestrians passing by or traffic
below.
Structural engineers have wrestled
with the problem for years and recently researchers at the University of
British Columbia in Canada think they have found a cure for concrete
cancer. Their study suggests that a cure
may involve “producing concrete using discarded glass.” Shahria Alam, an associate
professor of engineering and one of the authors of the report, says, ““Every
year, millions of tons of glass bypass recycling centers and end up in North
American landfills.” He explains that
their goal, like many engineers, is to try and make smarter building materials
without having to take a new resource out of the ground.
The researchers report that “By
partially replacing cement with polymer, fly ash and glass powder, we were able
to produce concrete that was more than 60% stronger than what was previously
believed possible.” They are looking to
further test their products but hope to eventually replace up to 25% of
traditional cement materials, mined from the earth with recycled glass.
The Conco Companies is one of the
leading concrete contractors in the Western U.S. and offer a wide range of
quality services and products. While we
tackle projects both big and small, our experience includes providing the
complete concrete package for the Levi’s Stadium along with other notable
projects. We serve California,
Washington State, Oregon, Colorado and Nevada.
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