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Glass Fibre Reinforced Plastics (GRP)

Glass fibre reinforced plastics (GRP) are used in a range of construction applications. A variety of GRP panels can be used as permanent formwork, for the decks of bridges, spanning between the main precast concrete beams. It is essential that the material is correctly specified as many commonly used resins can be attacked by the alkalis in concrete. Generally GRP permanent formwork will not contribute anything to the load-carrying capacity of the concrete (non-participating).

A developing form of construction is the use of glass fibre reinforced plastic tubes as permanent formwork for columns. In this case the GRP contains a significantly higher proportion of glass than in standard panels (possibly 60% of the cross-section). Depending on the orientation of the fibres, the tube can provide all, or the majority, of the reinforcement required for the composite column.

There have been a number of specialised applications of GRP in the water industry, for example in water supply tunnels. Here the GRP is mainly intended as a permanent liner but can also act as permanent formwork for the concrete.

Acknowledgement: The Concrete Society

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Permanent formwork in construction