Material properties - Reinforced Concrete with FRP Bars: Mechanics and Design - page 21

Material properties
2.1 INTRODUCTION
Even though other fabrication methods (e.g., braiding) and other
fiber-reinforced polymer (FRP) forms (e.g., two-directional grids) are
commercially available, this chapter intentionally deals with FRP bar
products fabricated by pultrusion. A brief summary of the properties of
the most commonly used types of fibers and polymers is provided as avail-
able in the ACI Guide 440.1R-06 [1], the FIB Bulletin 40 [2], and the
Italian CNR Guide [3]. From a reference perspective, the most authorita-
tive and comprehensive source of information on composites is the Wiley
Encyclopedia of Composites [4].
2.2 FRP BAR
An FRP bar is made of continuous fibers embedded in a matrix made of a
polymeric resin. The fibers have the function of carrying the load; the resin
has the function of binding together the fibers, transferring the load to the
fibers, and protecting the fibers. The fiber and volume fraction significantly
affect strength and stiffness of the FRP, while the resin type affects the
failure mechanism and the fracture toughness.
An FRP bar is anisotropic and can be manufactured using different tech-
niques such as pultrusion, braiding, and weaving. Other factors influencing
the properties of the bar are fiber orientation, rate of resin curing, manufac-
turing process, and quality control during manufacturing.
2.3 CONSTITUENT MATERIALS: FIBERS AND RESIN MATRICES
In this section, fibers and resin matrices that are most commonly used to
manufacture FRP bars are introduced and briefly discussed. Fiber and
matrix properties listed here are to be considered as generic.
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