Taking into account the high rehabilitation costs associated with the deterioration of existing concrete structures, mostly a result of steel reinforcement corrosion, the corrosion-free GFRP rebar could provide significant value for RC structures. Fiberglass rebar is now used significantly in many infrastructure applications, including bridge decks, pavements, walls, and other sensitive concrete systems. However, the construction industry is still reluctant to use GFRP reinforcing bars; this reluctance mostly results from the lack of long-term performance data of GFRP rebar embedded in concrete.
Significant research has been performed studying the durability of GFRP concrete reinforcement by measuring the reduction of mechanical properties after exposure to various environments. A study was recently conducted to examine the durability of GFRP reinforcement in concrete in different field structures across Canada. The purpose of the study was to uncover the true potential of GFRP composites and demonstrate the performance of GFRP reinforcement under harsh environments. To accomplish this, cores of concrete reinforced with GFRP were removed and examined from five different field structures.
In order to determine the condition of GFRP after being subjected to the corrosive environment of concrete for 5 to 8 years, researchers used techniques including optical microscopy, infrared spectroscopy, differential scanning calorimetry, and energy disruptive x-ray. As expected, results showed that no deterioration of GFRP reinforcement took place in any of the field structure. No sign of chemical degradation process was found. The overall results indicate that GFRP reinforcement is ideal for environments where traditional reinforcement can deteriorate quickly.
GFRP is now considered as a preferred material for concrete reinforcement in North America because of its corrosion resistance, economical competitive advantage, electromagnetic neutrality, high strength-to-weight ratio and excellent fatigue performance. The availability of in-practice data will further expand the scope of advanced composites in structural engineering.
In contrast with the results mentioned above, the results from other studies showed no physical or mechanical deterioration in the fiberglass rebar after 5-years of exposure to an extremely corrosive environment.
RC structures built with traditional steel offer the expected life of about 40 years in a corrosive environment, such as highway bridges with exposure to deicing salt ad waterside facilities. In marine structures, the corrosion of steel reinforcement leads to the rapid deterioration and loss of serviceability. As the corrosion of steel reinforcement has been a serious problem in infrastructural engineering, the use of corrosion-resistant GFRP reinforcement can permanently fix this issue. The replacement of steel with maintenance-free GFRP bar can save the construction industry billions of dollars every year.
TUF-BAR has been striving to design, manufacture and sell construction materials that can withstand the toughest environments and offer the service life of over 100 years. Our products include fiberglass rebar, rock bolts, concrete anchors, and form ties. Visit our site for more information.