Kent's Manston Airport is another former RAF base that has found a new lease of life as a civilian airport. Manston gained its CAA licence in August last year but a last minute hitch looked set to halt the sale of the airbase and illustrates the potential pitfalls of the conversion process.
'Facilities at Manston were excellent but the surface friction of the runway failed to meet the CAA's stringent safety standards, ' says Scott Wilson senior pavement engineer Niel Robinson.
'Manston's runway was resurfaced only eight years ago and, apart from surface friction, was in excellent condition. The problem only came to light at a late stage in the licence application because the MoD uses different test methods to the CAA and under the ministry's test the surface friction had conformed to its own standard.
Scott Wilson was brought in to provide specialist pavement advice to new airport owner, the Wiggins Group.
'There were a number of options available to resolve the problem, but conventional methods would have been costly and time consuming. With the licence hanging in the balance, however, time and cost were the critical factors, ' says Robinson.
Scott Wilson came up with a cost effective solution of directly overlaying the existing surface of the 2.75km long runway with a 20mm thick porous asphalt friction wearing course. After a rapid round of tendering the contract was awarded to Associated Asphalt, which proposed to use its large Scregg integrated macropaver to surface the runway in just six nights.
Robinson says: 'Associated Asphalt laid the wearing course at an amazing rate of up to 30m/min which meant all the work could be carried out during a series of six night possessions without any flight interruption. The porous overlay used a 10mm basalt aggregate, to give a high surface friction, and a 200 penetration polymer modified bitumen binder with quick setting characteristics to speed up the operation.'
The new wearing course passed the CAA friction tests, enabling the licence to be granted. The airport now mainly handles cargo and private flights but is ready and waiting to take scheduled and charter flights when demand becomes too much for the London airports.