FRP and TRM materials

FRP and TRM materials

development of the so-called textile reinforced mortars (TRM). Both FRP and TRM materials may be given the term “continuous fiber composites” or “advanced composites” or simply “composites”. For comparison with steel, typical stress-strain diagrams for unidirectional composites under short-term monotonic loading are given in Figure below. Uniaxial tension stress-strain diagrams for different unidirectional FRPs and steel. (Stijn Matthys, 2000) CFRP ＝ carbon FRP, AFRP ＝ aramid FRP, GFRP ＝ glass FRP In the following portion the three main components, namely matrices, adhesives and fibers of the composite materials strengthening system will be discussed as much as possible briefly. 2.1.1 Polymer matrices Polymeric matrices can be combined with carbon, glass, organic, or boron fibers to yield a wide class of polymeric composites with low density, high strength and stiffness, excellent chemical resistance and high fatigue resistance,. The main drawback of these materials is their relatively low temperature (in comparison with metals) resistance limited by the matrix. The polymer matrix of a fiber reinforced polymer material consists of a resin binder (polymer binder) and normally some additives and fillers. Primarily the matrix has to bind the fibers together, which can be provide lateral support to the fibers,

offer a load transfer medium, protect the fibers from their surroundings and may beneficially influence some FRP material properties. moreover, the matrix selection is also essential with respect to composite process ability and cost. The so-called thermo-mechanical curves are plotted to determine this important (for applications) characteristic of the matrix. For structural fire composites, among which FRP reinforcement for concrete, vinyl ester, unsaturated polyester and epoxy are used as polymer binder. From these resins, polyesters are the most general uses and frequently applied, given the better process ability, fairly good characteristics and low cost. Vinyl esters process is important like polyesters, but which provide improved chemical and mechanical performance. Epoxy resins are not cheap when compared with polyesters and vinyl esters, but are largely used in high-performance composites as they generally have the better mechanical properties, fantasy adhesion properties and excellent resistance to chemicals and solvents. Some typical properties of the above polymers are given below in table.