The M25 encircles the UK capital; at 118km it is one of the world’s longest orbital roads, used by up to 200,000 vehicles per day. The motorway was built between 1973 and 1986 and over this 13 year period, Shell Bitumen worked alongside many different contractors to deliver a variety of durable and reliable bitumen solutions.
The latest improvements comprise three different initiatives: 'Managed Motorway' (using the hard shoulders as running lanes), 'Controlled Motorway' (the introduction of variable speed limits) and conventional widening. All of these measures are designed to help to alleviate congestion but the key to increasing capacity lies in carriageway widening. This is being completed in phases.
'Section One' comprises junctions 16 to 23 and sees the motorway being extended from three to four lanes. The team, made up of the Highways Agency and Skanska Balfour Beatty, works round the clock. With over one mile of motorway being widened every month, it is also an extremely fast moving project; 450 operatives, 120 eight wheeled lorries, up to five slipfoam pavers and piling rigs can be in action at any one time.
The second section takes in Junctions 27 to 30 and is due for completion in summer 2012. A symmetrical approach has been adopted; one new running lane is added beside each carriageway. One lane of vehicles travels in contraflow on the carriageway opposite the works site.
Alongside the obvious requirements for the road surface to be durable, reliable and high performing, environmental concerns rank high for the DBFO contractor, Connect Plus Consortium. On the Section One site, approximately 92% of aggregates are from recycled sources, such as building site rubble.
Shell Bitumen’s contribution to the construction of the M25 is significant; in the late 1980s, Shell Cariphalte Dense Mixture (DM) was used on the M25 on what was one of the first ever polymer modified stretches of motorway in the UK. Today Shell continues to supply its innovative binders for both maintenance and the latest carriageway widening projects.
David Foster, UK & Ireland Business Manager for Shell Bitumen comments, "Our fondest and proudest memory stems from hindsight - it's great to know that both the M25 and Shell Cariphalte have stood the test of time. Both are both great examples of innovation. When compared to conventional bitumen, Shell Cariphalte is designed to offer stronger adhesion between the bitumen and aggregate, so helping to improve resistance to deformation and overall asphalt fatigue."
As the M25 approaches its 25th anniversary, Shell is proud to be part of its past and looks forward to helping build its future.