Seawater is an aggressive environment where concrete infrastructure such as seawalls, jetties, and water tanks deteriorate quickly. Corrosion of steel reinforcement or disintegration of concrete is the sign of deterioration of concrete structures. There is a number of factors affecting the deterioration of reinforced concrete in an aggressive environment. The ultimate service life of a structure and the severity of corrosion attacks depend on the environment in which a concrete member is situated.
Corrosion of steel reinforcement is one of the leading reasons why RC structures fail in marine environments. Water and salt ions penetrate through concrete cover and develop contact with internal reinforcement. This process leads to oxidation and corrosion of the rebar. Chloride-induced corrosion of reinforcement is considered as the leading cause of deterioration of concrete. The rust occupies volume and creates tensile stresses in the concrete which ultimately leads to spalling and cracking.
The sustainability and durability of RC structures particularly in marine environments remain a matter of big concern despite extensive research programs and many years of practical experience with reinforced and prestressed concrete. There are hundreds of examples of modern, steel-reinforced members that show signs of rebar deterioration providing with likely shorter serviceable lives than might be expected. In the coastal environment, corrosion of reinforcement is usually observed already after a few years and cracking/spalling of concrete occurs within 1-3 decades.
Most of the concrete deterioration has been linked to the excessive use of de-icing salts causing either salt frost attack on the concrete surface or reinforcement corrosion. Traditional rebar, no matter the protective layers or coating, cannot withstand the impact of de-icing salts and harsh coastal environments.
Sustainable marine infrastructure demands high-quality, corrosion-resistant materials. Fiber reinforced polymer (FRP) is the construction material which is not only high in tensile strength but also corrosion-resistant. FRP usually consists of fibers and polymer resin matrix. The glass fibers function as the reinforcement providing tensile strength, while, on the other hand, the resin surrounds the fibers providing corrosive resistance to the composite system.
The civil engineers are now increasingly adopting FRP technology to fight corrosion in marine structures. FRP composites have been used extensively in the recreational boating industry for more than 30 years. We are now beginning to see applications for more widespread uses of FRP in larger marine structures.
FRP composites can play a crucial role in building sustainable and maintenance free marine structures. Countries like the US and Canada cannot undermine the significance of marine infrastructure. Thorough planning and corrosion-free construction strategies can save these countries billions of dollars every year. The construction industry now clearly understands how costly it is to repair or rehabilitate deteriorated concrete members.
Rehabilitation of corroded and deteriorated members is a very expensive activity. In order to avoid costly maintenance and repair, the construction industry should start exploring and using FRP materials at large scale.
TUF-BAR designs and manufactures fiberglass rebar which is a stronger and lighter alternative to conventional steel. Our GFRP products including fiberglass rebar are specified for use in bridges, dams, barrier walls, tunneling and other sensitive marine applications. Visit our site for more information!