Edinburgh airport is one of the fastest growing airports in the UK. To improve operations at the airport and keep pace with the rapid rise in air traffic, a planned programme of expansion is underway, including the construction of a parallel taxiway. To ensure that the new taxiway is able to withstand the high loadings imposed by aircraft, a layered pavement foundation has been developed incorporating an Enkagrid MAX geogrid supplied by Maccaferri Ltd, specialist in retaining structures, soil reinforcement and erosion protection.

65,000m² of 30kN/m biaxial geogrid was specified by main contractor Amec Construction to form part of a complex layered foundation solution developed in consultation with BAA’s pavement & infrastructure team. In one of its largest supply projects in Scotland to date, Maccaferri’s excellent stock availability enabled it to deliver the quantity required to the site within the time frame stipulated contractor.

Built on sandy clay, when complete the new taxiways will be up to 23 metres wide and approximately two kilometres in length. The Enkagrid MAX was installed within a 700mm layer of capping material. A layer of geosynthetic separates this from a 150mm layer of Type 1 fill topped with a 150mm layer of lean concrete and 420mm of pavement quality concrete.

The order was won following a competitive tender process. Maccaferri was able to demonstrate effectively that its Enkagrid MAX geogrid fulfilled the design specification and could be supplied at a very competitive price.

Manufactured by Netherlands-based Colbond Geosynthetics, Enkagrid MAX is a low-cost biaxial polypropylene geogrid specifically designed for sub-base stabilisation. Offering maximum bearing capacity and shear resistance, its unique structure of chemically inert precision laser-bonded extruded polypropylene strips delivers high resistance of UV degradation, elevated bearing resistance and optimum interaction in most soil types.

Easy and quick to install, Enkagrid MAX was delivered to Edinburgh Airport in five metre wide rolls. This was significant as it reduced the number of overlaps required to cover the 22 metre width of the taxiways. Each roll of Enkagrid MAX is 100 metres in length.

Colbond Geosynthetics manufactures and supplies a range of high quality geosynthetic products for civil engineering applications. The range of products includes Enkamat, Enkadrain, Enkagrid, Colbonddrain and Armater. Based on polymer technology, these products are used all over the world for erosion control, drainage, waste containment and soil reinforcement and improvement.

Maccaferri Ltd specialises in the supply of gabions, geotextiles, geogrids and geomats. In addition to a full range products for gabion, timber crib and segmental concrete retaining walls, the company also offers a wide choice of solutions for soil reinforcement and erosion protection, including an in-house design and advice service.