reinforced concrete is a very common material for construction of facilities and structures. In addition to the limited tensile strength of concrete, steel bar reinforcement has been a profitable and efficient. However, insufficient concrete cover, poor design or workmanship, and the presence of large amounts of aggressive agents and environmental factors can lead to rupture of concrete and corrosion of reinforcing steel. For example, in Colombia for almost 45% of puentes son estructuralmente deficientes o funcionalmente obsoletos, y el porcentaje va en aumento, según algunas entidades durante muchos años, ha habido muchos estudios en cuestión a la corrosión, y el interés en FRP (polímero reforzado con fibra) ha surgido recientemente como posibles sustitutos para el acero. Una cuidadosa consideración sobre el potencial de barras de refuerzo de FRP para llenar las necesidades de costes y el rendimiento pueden sugerir soluciones apropiadas.
Recientemente, los materiales compuestos de fibras incrustadas en una resina polimérica, también conocido como polímeros reforzados con fibra, se han convertido en una alternativa al refuerzo de acero para concrete structures. The reinforced polymer aramid (AFRP), the reinforced polymer carbon fiber (CFRP) and reinforced polymer fiberglass (FRP) bars are the products available in the market for construction industry. These materials have been proposed for use in place of steel reinforcement or prestressing steel tendons in concrete structures. The steel corrosion problems are avoided with the use of FRP as these are non-metallic materials and non-corrosive. also FRP materials have several properties such as high voltage resistance make them suitable for use as structural reinforcement. Moreover, codes and design provisions have been recently prepared for the use of FRP bars in concrete structures for bridges and buildings.
binding characteristics are responsible for transferring the load of concrete to strengthen and develop the necessary tension in the reinforcement for balance, especially when the concrete cracks . fiber reinforced polymers are anisotropic materials . Factors such as the type and amount of fiber and resin, fiber orientation and quality control during manufacturing play an important role in the mechanical properties. In the case of FRP reinforcing bars carbon (CFRP Isorod Pultrall bar, ADS Composites Group), by comparing a steel bar of 11.3 mm in diameter with CFRP reinforcing bars with a similar diameter of about 9.5 mm, the results show that the stress-strain curves to the drawbar of CFRP is linear up to rupture (All FRP bars is linear elastic to failure). The tensile strength is at least 1500 MPa, three times that of the bars acero.El modulus CFRP bar is 128 GPa, approximately 65% \u200b\u200bof steel. The CFRP bar showed almost the same bond strength to concrete as a steel bar of 11.3 mm in diameter. As for the glass FRP bar has tensile strength of a bar GRP 9 mm is 760 MPa, and modulus of elasticity is 40.8 GPa, much lower than that of steel .
FRP bars can be a suitable alternative in the following cases:
Recientemente, los materiales compuestos de fibras incrustadas en una resina polimérica, también conocido como polímeros reforzados con fibra, se han convertido en una alternativa al refuerzo de acero para concrete structures. The reinforced polymer aramid (AFRP), the reinforced polymer carbon fiber (CFRP) and reinforced polymer fiberglass (FRP) bars are the products available in the market for construction industry. These materials have been proposed for use in place of steel reinforcement or prestressing steel tendons in concrete structures. The steel corrosion problems are avoided with the use of FRP as these are non-metallic materials and non-corrosive. also FRP materials have several properties such as high voltage resistance make them suitable for use as structural reinforcement. Moreover, codes and design provisions have been recently prepared for the use of FRP bars in concrete structures for bridges and buildings.
binding characteristics are responsible for transferring the load of concrete to strengthen and develop the necessary tension in the reinforcement for balance, especially when the concrete cracks . fiber reinforced polymers are anisotropic materials . Factors such as the type and amount of fiber and resin, fiber orientation and quality control during manufacturing play an important role in the mechanical properties. In the case of FRP reinforcing bars carbon (CFRP Isorod Pultrall bar, ADS Composites Group), by comparing a steel bar of 11.3 mm in diameter with CFRP reinforcing bars with a similar diameter of about 9.5 mm, the results show that the stress-strain curves to the drawbar of CFRP is linear up to rupture (All FRP bars is linear elastic to failure). The tensile strength is at least 1500 MPa, three times that of the bars acero.El modulus CFRP bar is 128 GPa, approximately 65% \u200b\u200bof steel. The CFRP bar showed almost the same bond strength to concrete as a steel bar of 11.3 mm in diameter. As for the glass FRP bar has tensile strength of a bar GRP 9 mm is 760 MPa, and modulus of elasticity is 40.8 GPa, much lower than that of steel .
FRP bars can be a suitable alternative in the following cases:
- Architectural Concrete: artificial stone cladding architectural, balustrades, facades, column, architectural precast, railings, statues and fountains, etc.
- Concrete exposed to de-icing salts in: crossings, median barriers, elements of garage and salt storage facilities, etc.
- Concrete exposed to sea salts, dams, water breaks, the buildings and structures near the beach, aquaculture operations, and floating docks, etc.
- Concrete used around electrical equipment such as MRI rooms in hospitals, the airport radio and compass calibration pads, transformers, substations, etc.
- Impervious to chloride ion and chemical attack.
- greater tensile strength than steel.
- 1/4th weight of steel reinforcement
- Transparent to magnetic fields and radio frequencies
- Electrically and thermally nonconductive
B roasted above characteristics, bars FRP appears to be a promising alternative reinforcement for concrete structures such as marine structures, parking structures, bridges, roads in extreme environments, and structures highly susceptible to corrosion and magnetic fields.
MAIN BARRIERS TO THE USE OF FRP BARS:
The cost of FRP reinforcing bars in $ / ft is often superior to conventional steel bars. The carbon FRP is generally more expensive than GFRP. to find a detailed catalog of the cost of FRP reinforcing bars clik here. Note that you can not make a substitution direct FRP steel bars without applying the design principles of the guide. In general, the cost impact of using FRP bars in a bridge deck is just raising the cost of the package for something on the order of 2 to 5% in those days. Therefore, using GFRP bars and win many more years of life is not really an expensive alternative.
- The cost is $ 3 to $ 4/lb (including approx. $ 1/lb the cost of raw materials) for FRP rod of glass, carbon and FRP is usually more expensive. (cf. Epoxy coated rebar costs $ 0.32/lb) (As the cost of epoxy-coated bars $ 0.32/lb)
- Due to the lack of well established rules, a wide variety of FRP bars are marketed today, the move from simple plain bars bars treated to improve the characteristics of the ligaments. therefore requires a better understanding of the mechanical properties and behavior of links to a rational approach to the design of FRP reinforced structures.
- field curves are not allowed, and are not welded, as opposed to the construction operations ordinary steel bars should be applied from the design phase.
- The lack of familiarity of engineers can lead to decreased productivity of the projection.
