"The extension of the M77 Motorway with the Glasgow Southern Orbital (GSO) creates the largest road construction project undertaken in Scotland in recent times.

The 130m, Design, Build, Finance and Operate (DBFO) project will improve a vital part of Scotlands strategic road network which is essential to continuing economic growth, particularly in Ayrshire and SW Scotland. It will also provide direct links with other arterial roads serving the central belt, the south of Scotland and the ferry routes to Ireland."

The trio of speakers gave an in depth and detailed talk on this huge project. Subjects covered included funding phasing, tendering, construction period and progress to date.

Since the tendering procedure in February 2002 and the eventual appointment of Connect in November 2002 after the consideration of 17 bids, the project officially commenced in April 2003.

Since then a total of 72 structures have been completed including 14 new bridges.

A project video was shown which highlighted some of the obstacles that the project team had to overcome, such as the difficulties presented by the presence of peat during the earthworks stage. Around 200,000 tonnes of rock fill was utilised, and lime added to unsuitable material to lower the moisture content making it suitable for fill.

Some statistics from the project;

• 71 utility diversions
• 3,000,000 cu.m of earthworks
• 2,000,000 tonnes of quarry products
• 500,000 tonnes of surfacing (18,000 t/week)
• 40km of kerbing
• 1000 employed on project (peak)

Summary of Foam Bitumen Presentation

Gordon McCabe of Linear Quarry Products Ltd gave a very detailed and entertaining technical presentation on the uses and benefits of Durafoam - foam bitumen macadam.

The foam bitumen process starts with recycled bituminous material which is screened and blended on site. Cold water and compressed air is then injected into hot bitumen which creates a steam filled foam. On contact with the cold recycled material this mix disperses leaving fine threads which become coated with dust. It is this combination of bitumen and fines that bonds the material together during the compaction.

Tarmac's Wirtgen KMA150 is a mobile recycling plant capable of producing 150 tonnes per hour.

Coring and tests taken across the UK confirm that the foamix is equivalent to 100pen DBM. See TRL report TRL611 for full details.