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It’s estimated that more than $5 billion is spent each year to rebuild concrete structures damaged by corrosion. We see this damage daily on balconies, bridges, parking garages and other steel reinforced concrete structures. |
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The characteristics of new concrete naturally
inhibit the corrosion process. However, over time, unprotected concrete
exposed to the combination of chlorides, water and oxygen will create a
corrosive environment for reinforcing steel. Once established, this electrochemical
reaction will begin to corrode steel, thereby expanding its volume. This
expansive force directly leads to the cracking and spalling of concrete,
reducing structural integrity.
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The Corrosion Cycle The first cycle of corrosion and spalling
may not occur for 10-20 years, as contamination of the concrete builds
up. Once contaminated, the corrosion will continue and repairs may
be needed every 3-5 years unless corrosion is effectively stopped.
Traditional methods of repairing the spalled areas, chasing corrosion,
treating exposed rebar, and/or waterproofing the concrete may not stop
corrosion from propagating. In fact these procedures could accelerate
the corrosion process.
Meeting The Challenge “Cathodic protection is the only means
to control corrosion on steel reinforced concrete structures that have
chloride contaminated concrete”
“When chlorides are present in excess of
the threshold, the use of sealants and waterproofing membranes will not
stop corrosion and may accelerate it”
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