Highways

M25 Resurfacing Concrete Bay Replacements

Concrete bay replacement on a live motorway is a race against the clock, and TAG's method on this M25 resurfacing scheme for Connect Plus, Skanska and Osborne was built to win it. The first night-time lane closure was used to saw cut the carriageway into sections; TAG's vacuum lifter then pulled a whole bay out in minutes, ready for a new one to go in on the following possession.

Speed came from the detail as much as the headline lift. Dowel holes were drilled with an EZ slab rider drill purpose-built for accurate, fast concrete drilling, cutting each hole to five minutes against the traditional hour. The rapid-cure concrete used to replace each bay behaves very differently to a standard mix, and TAG's teams learned to work with it rather than around it.

The numbers tell the story: conventional repairs and materials take a minimum of four nights and a day to replace a single bay. TAG's system replaced up to two bays a night, with capacity for more within the same closure window, over a three-month contract.

The technique's success didn't stay on the M25. TAG went on to trial the same vacuum-lift method for Ferrovial Agroman at Heathrow Airport, lifting 500mm-deep PQ slabs from the taxiways and aprons, and again at London City Airport, where local residents noticed the difference too, the vacuum method generating far less noise than a conventional breakout.

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