Composite Rods as a Steel Substitute in Concrete Reinforcement

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Introduction
The concrete construction industry is dealing with a very significant challenge regarding the
deterioration of structures. Nowadays a large number of bridges, buildings and other structural
elements require rehabilitation and repair and its maintenance have become an increasingly serious
problem. Once subjected to repeated loading and to aggressive environmental agents, concrete
structures present a decrease of mechanical properties and of durability performance, being the
corrosion of steel one of its most serious problems.


Objective of the research work, experimental work and results obtained
The current research work deals with the development of braided reinforced composite rods for
civil engineering applications, namely to reinforce concrete structures as a substitute of steel rebars.
The mechanical properties of FRP rods, produced by braiding, are influenced by the type of fibre
used as braided fabric core reinforcement, among other parameters. The objective of this
experimental work is to evaluate the influence of the type of core reinforcement fibres on the
mechanical performance of braided reinforced composite rods. Several samples of braided
reinforced composite rods were produced using polyester fibres, for the production of braided
fabrics, E-glass, carbon and HT polyethylene fibres, as braided fabrics core reinforcement, and
polyester resin as polymeric matrix. Braided reinforced composite rods have been produced on a
vertical braiding machine with an incorporated impregnation system.



Braided reinforced composite rod tensile performance ranking
In order to identify which is the braided reinforced composite rod that presents the most
interesting tensile performance, a classification criterion was defined. Thus, was established a score
from 1 to 7, namely, for the best and worth tensile performance in each parameter evaluated (Table
3). Therefore, the composite rod that presents tensile performance according to the objectives
envisaged is the one that presents the smallest total score. The composite rod that presents the
highest total score value is the one which tensile performance is less interesting, among the
composite rods produced.