A new video shows how contractors on a scheme to resurface a key section of the M23 used an innovative technique to get the job done ahead of a £164m upgrade to a smart motorway.
The motorway connects Crawley and Gatwick Airport to the M25, with Junction 9 a key access point for traffic to and from the airport.
More than a decade ago, a section of the M23 London-bound between Junctions 9 and 10 was laid with a pioneering trial of ‘whisper concrete’. With this reaching the end of its life cycle and a £164m all lane running smart motorway upgrade due to begin in spring 2018, it was essential that the ageing surface was removed and an upgraded asphalt replacement laid.
Highways England, lead contractor A-one+ and supply chain partner Tarmac worked together to create a scheme that would minimise disruption to road - and airport - users.
Power-saws were used to cut the concrete into 2.5m x 1.85m sections, with around 375m of surface prepared in this way each Thursday night ahead of four weekend working windows.
Inspired by technology used in the USA, the team collaborated with contractor LMS Highways to design a specially adapted excavating bucket capable of lifting and scooping up the concrete slabs. The elongated base of the bucket and wedge-shaped teeth fully supports the slabs, allowing them to be placed for easy extraction without the risk of fracturing.
The entire supply chain came together to devise the innovation – the first time this style of machinery adaptation has been used in the UK. Because the new technology is built on existing machinery, evolution rather than revolution meant that the teams involved in the project could be quickly trained in its operation.
More than 3,900 tonnes of concrete were crushed and recycled, turning the material into a sub-base product that will be used in the construction of new roads.
Although work was rained off during the project's second scheduled weekend and had to be rescheduled, the carriageway was completed last month.
You can read the full story of the project in the June issue of Highways magazine.