CARBON FIBERS AND THEIR APPLICATION IN CIVIL ENGINEERING 6 from 7

often affects the bonding quality greatly because of the uneven- mess of the concrete surface.

Not just CFRP plate, even the CFRP sheet is similar in nature, because it must beimpregnated by resin before its regidification and only then it can be tensioned and bonded to the structural surfaces.

Also, external pre-stressed cables have proved to be a good alternative for steel cables with good durability and first rate behavior in creep and relaxation.

These pre-stressing techniques also have a few disadvan- tages and are thus undergoing research for betterment.

Challenges and future for carbon fibers in construction industry

One big restriction on making extensive use of carbon fibers in the infrastructure technology is their considerably high cost.

While prices have dropped significantly in the past five years, demand has not increased enough to increase the supply sub-  stantially.

As a result, prices will likely remain the same for the near future.

One way to manage this drawback is by making use of FRP hybrid systems.

Since FRP composite materials have a higher initial cost, hybrid FRP systems that combine the high stiffness and or high compression strength of conven

– tionalmaterials have proven to be effective.

For example, to reduce the cost, aramid FRP may be used in a component where the tensile stresses are high and carbon FRP may be used in the section undergoing compressive stresses) as both are excellent in respective properties.

Similarly, combi- nation of glass FRP and other such types, depending on the structurere- quirement, might prove cost effective.

Using carbon fiber reinforcement bars may also become a reality in near future, as it undergoes intense research worldwide.