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This part analyzed GFRP rebar’s research situation, summarized its behaviuor as internal
reinforcement for concrete structures. The research has been developed over recent years, however
the rules and standard codes for design RC concrete structures with these rebars not consider that
the internal reinforcement can work in compression. This paper presents the development of the
research to get a new kind GFRP rebar for work as internal reinforcement of concrete structures,
with an innovative design for work both in tension and compression, and their mechanical
properties: strength, bond,…
The use of fiber-reinforced bars polymer (GFRP) to enhance the corrosion behaviour of
conventional reinforced concrete structures, appears as one of the many techniques presented [1, 2].
In particular, the GFRP bars offer great potential for use as reinforcement in conditions in which
reinforced concrete with steel offers unacceptable conditions of service [3, 4]. Therefore, the use of
GFRP as armed bars of concrete has been in development since the early 1960's in America [5] and
the 1970 in Europe [6] and Japan [7], although the overall level of research, demonstration and
commercialization has increased markedly since the 1980's, using mainly GFRP reinforced concrete
in structures that require high resistance to corrosion or electromagnetic absolute transparency
The bars GFRP are normally manufactured by the pultrusion process or a variant such as "pull-
forming." This type of process makes it possible to obtain products with high fiber content, 60% and
80% of its volume, and a homogeneous distribution of fiber in the bar cross section. Typical GFRP
reinforcement products are grids, bars, fabrics and rods. The bars have various types of cross-
sectional shapes (square, round, solid and hollow) and deformation systems (exterior wound fibers,
sand coatings and separately deformations). Rovings have a high tensile strength and high modulus
of elasticity, in addition to being the resistive component of the composite. The matrix is the
required material used to bind the fibers to obtain a homogenization among them, but also serves to
confer protection and dimensional stability of the GFRP bar.
The mechanical behaviour of GFRP reinforcement differs from the behaviour of conventional
steel reinforcement. The analysis of sections reinforced with GFRP, bending and shear, in many
cases is compared to conventional analysis of steel sections, although the significant differences in
terms of properties and mechanical behaviour, so a change is need in the traditional design
philosophy. GFRP composites have a linearly elastic stress-strain relationship until failure, no yield,
which means that the systems used to design reinforced concrete with this type of reinforcement
must take into account the lack of ductility that has the material, unlike steel reinforced concrete.
Currently, the reinforced concrete with GFRP bars is designed using the principles of Ultimate
Limit States, ensuring a sufficient strength (with a design safety factor affecting loading and
material strength), determining the failure mode and verify adequate adhesion between the
materials. Service Limit States, such as deformation, cracks, resistance to fatigue or long-term loads
and relaxation (for prestressed concrete), must also be checked.
Advanced Materials Research Vols. 457-458 (2012) pp 553-556
Online available since 2012/Jan/24 at www.scientific.net
© (2012) Trans Tech Publications, Switzerland
doi:10.4028/www.scientific.net/AMR.457-458.553
All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP,
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