How Long Can FRP Coatings Sustain Concrete Structures?

Brief 

An experiment lasting 13 years tested the viability of glass- and carbon-fiber-reinforced polymer coatings as a means to externally add strength to concrete structures. Researchers observed significant differences in debonding in indoor and outdoor environments.

Insight

Fiber reinforced polymer coatings are an affordable way to externally strengthen concrete structures, but how long does the protection last? Scientists find out.

One potential cost-effective way to sustain ageing concrete subjected to harsh environmental conditions is to externally coat the material with fiber reinforced polymer composites. But few studies have looked at the durability of such strengthening. Now, researchers from Korea and the USA conduct a 13-year long experiment to find out.

In modern society, we find that the majority of our infrastructure (buildings, bridges, tunnels, etc.) is made of ageing concrete. A recently developed cost-effective method of sustaining this infrastructure is external coating with fiber reinforced polymer (FRP) composites. But is this a temporary patch or a durable solution? Not much research has looked into this question.

Now, a 13-year-long study published in Composites Part B finally finds out, taking us one step closer to the wide-spread utilization of this solution.In the FRP-strengthening of concrete, glass or carbon fiber reinforced polymer (GFRP or CFRP) composites are bonded onto concrete using an epoxy adhesive.

These sheets provide additional support and strengthen the concrete structures by protecting them from harsh environmental conditions, such as high moisture levels and temperatures. But the problem is, these same environmental conditions can potentially degrade the concrete-FRP bond as well, causing the FRP protection system to fail prematurely.

Prof. Jaeha Lee from Korea Maritime and Ocean University, a lead researcher in the 13-year study, says, “The information available on FRP-concrete bond behavior following sustained loads in different environments is very limited, particularly for periods beyond two years.”