Experience of development and application FRP-Rebar in USSA
The interest to the fiber reinforced Plastic Bar has arisen in middle XX of century in connection with a number of circumstances. The application of the reinforced concrete designs in responsible structures maintained is strong aggressive environments has extended where it was difficult to ensure corrosion resistance of the steel armature. There was a necessity of maintenance antimagnetic and dialectric properties of some products and structures. And, at last, it is necessary to take into account on prospect limitation of a stock of ores, suitable for satisfaction of continuously growing needs in steel and always scarce.
As a carrying basis of the developed high-strength FRP-Rebar at first it was accepted continuous alkaliresistance a glass fiber by a diameter 10-15 mc, which bunch was united in a monolithic core by means of synthetic pitches (epoxy, epoxyphenol, polyester etc.).
In USSR (Minsk, Moscow, Kharkov) was developed continuous technology of manufacturing of such fixture by a diameter of 6 mm from alkaliresistanceof fiber glass of the stamp CH-15 GT, its physic-mechanical properties are in detail investigated.
The special attention was given to study of chemical resistance both durability of fiber glass and fixture on its basis in concrete in various aggressive environments. The opportunity of reception glassfiber reinforced plastic bar with the following parameters is revealed: temporary resistance to break up to 1500 MPa, initial module of elasticity 50 000 MPa, density 1,8-2 t/m3 at the weight contents of fiber glass 80 %, the working diagram at a stretching is rectilinear down to break, the limiting deformations to this moment reach 2,5-3 %, the long-term durability of the fixture in normal temperature-humidity conditions makes 65 % from temporary resistance, factor of linear expansion 5,5-6,5*10-6.
The skilled previously intense bent elements with FRP-Rebar under influence of static loadings were comprehensively investigated, the technological rules on manufacturing the fixture and recommendation for designing concrete designs with the FRP-Rebar are developed, the expedient areas of their application are planned.
Experimental samples isolater electric of support LET were developed, the made copies are established on skilled sites of transmission lines in Byelorussia, Russia and Ajary. The researches on use GFRP-Rebar in support of a contact network and in pressure head pipes are carried out. GFRP-Rebar has found also application in baths from polymer-concrete in shops electrolis at the enterprises of colour metallurgy, in plates in several warehouses of mineral fertilizers.
Source: ACI 440.1R-06 Guide for the Design and Construction of Structural Concrete Reinforced with FRP Bars. (Reported by ACI Committee 440)