FRP (Fibre Reinforced Polymer) is a product made up of two or more materials which when used together adopt characteristics of both materials, in a similar way that steel reinforcement is used in concrete to add tensile strength to the compressive strength of the concrete to create an extremely versatile building product.
Usually FRPs are made up in layers of a flat material such as Carbon Fibre, Aramid (Kevlar) or Glass sheets which is embedded into a resin matrix product are wrapped around the element to be strengthened and embedded into a resin matrix material normally polyester, epoxy or nylon.
The fibres of the sheet material provide the strength and the matrix secures them in place, transfers the load evenly amongst the fibres and acts as the protector and bonding to the surface of the element.
Composite strengthening is used for :
- Repairing damaged or deteriorated concrete (caused by corrosion of embedded reinforcement)
- Increasing strength (where a change of use requires modification or increased loadings are expected).
- Seismic or wind load design requirements (laminate layers increase flexibility without greatly increasing weight)
- Blast mitigation (some FRP materials are ideal for protecting structures against explosions etc)
This method of strengthening gives increased strength with minimal additional weight, it can be applied quickly, making it a fast solution with low future maintenance costs making it a cost effective alternative to adding new columns or beams or external post strengthening.