TITLE:
Enhancement in Elastic Modulus of GFRP Bars by Material Hybridization
AUTHORS:
Dong-Woo Seo, Ki-Tae Park, Young-Jun You, Hyeong-Yeol Kim
KEYWORDS:
FRP; Glass Fibers; Tensile Test; Elastic Modulus; Pultrusion; Material Hybridization; Marine Structures
JOURNAL NAME:
Engineering,
Vol.5 No.11,
November
6,
2013
ABSTRACT: Fiber reinforced polymer (FRP) reinforcing bars for
concrete structure has been extensively investigated for last two decades and a
number of FRP bars are commercially available. However, one of shortcomings of
the existing FRP bars is its low elastic modulus, if glass fibers are used (i.e., GFRP). The main objective of this
study using the concept of material hybridization is to develop a viable hybrid
FRP bar for concrete structures, especially for marine and port con- crete
structures. The purposes of hybridization are to increase the elastic modulus
of GFRP bar with acceptable tensile strength. Two types of hybrid GFRP bar were
considered in the development: GFRP crust with steel core and GFRP bar with
steel wires dispersed over the cross-section. Using E-glass fibers and
unsaturated polyester resins, the hybrid GFRP bar samples of 13 mm in diameter
were pultruded and tested for tensile properties. The effect of hybridization
on tensile properties of GFRP bars was evaluated by comparing the results of
tensile test with those of non-hybrid GFRP bars. The results of this study
indicated that the elastic modulus of the hybrid GFRP bar was increased by up
to 270 percent by the material hybridization. The results of the test and the
future recommendations are summarized in this paper. To ensure long-term
durability of the hybrid GFRP bars in waterfront structure applications, the
individual and combined effects of environmental conditions on hybrid GFRP
rebar itself as well as on the interface between rebar and concrete should be
accessed.