The concern with the deterioration of conventional building materials, such as steel and concrete, is growing worldwide. A recent shift to the use of fiber-reinforced polymer (FRP) construction materials, as an alternative to traditional concrete reinforcement, has largely been witnessed. Fiberglass reinforcement is non-corrosive and offers high modulus values and strength. The distinguishing properties of FRPs, such as tailored design, deformability, and weight, has enabled the structural rehabilitation of existing concrete structures reinforced with traditional material.
With a wide application prospects in civil engineering projects, FRP materials have turned out to be the best reinforcement that has the strength to protect a construction from external elements such as corrosive agents and heat. Fillers, reinforcing fibers, and polymer matrix are combined together to produce bulk material. The properties gained by combining these elements are better than the individual properties of used materials.
Thermosetting (polyester, vinyl ester, epoxy resins etc.) or thermoplastics can be the matrix. Fibers, used to reinforce polymer, are employed to enhance the mechanical properties such as strength and stiffness. Carbon, aramid, and fiber are the primary sources that carry load. The role of polymer matrix is to protect fibers and combine them as a cohesive structural unit. Automobile, marine, and aerospace industries have expanded the use of advanced composite materials for their engineering properties that include high strength, stiffness, high fatigue endurance, and low thermal coefficient.
Glass fibers and protective mechanism:
In most of the composite applications, glass fibers are used largely because they are inexpensive. S-glass, E-glass, and AR glass are the different forms that have varying strengths and properties. Glass fiber reinforced polymer (GFRP) bars are very efficient in protecting concrete structures from various external threats enabling engineers to construct high strength and rust free projects.
Some of the major characteristics of glass fibers are moderate elastic modulus, high tensile strength, and excellent thermal and electric insulation. Resin system used in the fiber-reinforced polymer protects the glass fibers from moisture, alkalinity, and salts. Salts, water, and alkalinity are some of the main corrosive agents that seriously damage the integrity of a concrete structure.
Functions of the matrix:
Some of the critical roles played by matrix are:
- To protect the surface of fibers from environmental degradation and abrasion
- To disperse and separate fibers within the composite in order to avoid propagation of cracks
- To limit smoke propagation
- To remain thermally and chemically compatible with fibers
- Fire resistance and good aesthetic finish
It is the mechanical characteristics of GFRP bars that make them strongly effective against corrosion. The use of fiberglass rebar in civil engineering, therefore, is on the rise.