COMPOSITE PILES form a key part of plans to find an alternative to rainforest timber for construction and repair of beach groynes around British coasts.
The piles have casings of inner glass fibre winding, resin bonded to an outer skin of high density polyethylene (HDPE). These are filled with concrete insitu once the casing has been jetted into place. They support recycled plastic panels driven into the sand.
Developed by recycled plastic specialist Plasti, the system is being funded by the Department of Trade & Industry under its SMART scheme for small business innovation.
Assembly of the first recycled plastic test panel took place in January. Supported by the composite piles, the panel will undergo full scale trials on Bournemouth beach on England's south coast from October. Tests have already proved the viability of the composite pile, said Plasti managing director David Croucher.
The 2.7m deep by 7.5m long test panels will be made up of 100mm x 100mm recycled HDPE planks.
These are stiffened by pultruded glass fibre reinforced plastic sections bolted tightly together to resist erosion from Bournemouth's very fine sand.
'Erosion at the horizontal joints between the planks of groynes is our biggest problem, ' said Bournemouth Borough Council principal engineer Dr David Harlow. 'We have to replace two of our 54 timber groynes every year at a cost of £200,000 each.'