Concrete is the world’s
most widely used construction material. Although extremely durable, its chief
vulnerability is corrosion. This occurs more readily on aging structures but
can also attack new concrete located in hot, humid seaside climates or regions
that rely heavily on deicing salts. Accordingly, rows upon rows of green
epoxy-coated rebar are often seen staged at construction sites for enhanced
protection. However, it is important that engineers and contractors understand
this may not be an end-all to their corrosion worries and they need to be aware
of alternative methods for overcoming the deficiencies of epoxy-coated rebar.
Epoxy
Coating Deficiencies
If the epoxy coating on
rebar were to remain undamaged, it would provide exceptional protection by
creating a thick barrier to corrosives. Unfortunately, coating damage is
all-too-common. As epoxy-coated rebars roll off the paint line and get bundled
for shipment to some jobsite, their most vulnerable stage begins. Cortec® CEO,
Boris Miksic, pointed out that, “When coated rebars are transported, bent,
welded, and installed there is a great probability that the coating will be
physically damaged. The damaged areas will be[come] small anodes coupled to
large coated areas [that become] cathodes, causing pitting failures.” The
question, then, is how to find a backup technology that inhibits corrosion at
these points.