Materials

Fiber reinforced polymer materials are made of a matrix with the purpose of shaping and structuring the material and the fiber which must support tensions.
They are stuck onto the elements to be reinforced using specific epoxy adhesives and connect to the structure to improve load-bearing.

The fibers used are part of three families: glass fibers, carbon fibers, aramidic fibers and their main features is tensile strength and lightness. Among these, carbon fibers feature the highest tensile strength and elasticity modulus. For this reason they are used more often than the others in structural reinforcement operations. Carbon fiber reinforce polymers are also referred to with the acronym CFRP.

Table with fiber properties (See technical sheet)

As for polymer matrix, epoxy resins are used thanks to extremely reduced shrinkage and excellent chemical resistance which makes them stable both in an acid (air pollution) and in a basic environment (concrete alkalinity).
Moreover, adhesion to most supports, whether dry or damp, is excellent; when application is carried out workmanlike, tear test will result in break of the support, but not the removal of the reinforcement.

Areas of use

• Reinforcement of concrete works: floors, beams and pillars
• Reinforcement of stone and brick works: pillars, columns, vaults, arches, cupolas
• Structural reinforcement of beams in floors and wooden tie beams
• Adjustment of the load of buildings for new uses.
• Seismic adjustment of concrete, stone and brick frameworks

Advantages of carbon fiber reinforced polymers (CFRP)

• Top mechanical features (high performance/weight ratio)
• High stiffness of the reinforcement and tensile strength
• Operations are easy thanks to light and easy to handle reinforcements: straps can be cut with a pair of scissors.
• Completely corrosion-free
• They do not alter the original shape of the reinforced elements
• The operation is reversible

The comparison with traditional methods
Traditional techniques on compressed elements require bracing using metal strips and ties, or by increasing the resistant section by applying highly resistant anti-shrinkage mortars.
In case of inflected structure restoration, the most common and used technique is the beton plaqué which uses metal plates glued to the structure using epoxy adhesives to provide reinforcement.
In case of masonry vaults the traditional operation requires casting a layer of grout with hydraulic binder on the extrados of the vault.

Products for carbon reinforcement materials: