The motorway management company, a joint venture between Balfour Beatty, Skanska, Atkins and Egis, has introduced Rapid Cure concrete, which it says cuts the time needed for motorway lane and carriageway closures from 1500 hours a year to just 300.
Connect Plus, working with its supply chain partners, developed the Rapid Cure technique from best practice in the aviation industry where it is used for repairing airport pavements. It works by introducing a super-plasticiser chemical and a curing accelerator to the concrete mix that makes it set more quickly. The surface still reaches the required compressive strength of 25N/mm2.
Connect Plus has also introduced other techniques to reduce the duration of concrete repair works including pre-cutting the old concrete and preparing it with lifting eyelets for quicker removal and the use of quick drying heated tents. This complete process from start to finish, including the removal of the old concrete bay and the laying out of traffic management, now takes one overnight closure compared to the previous full forty-eight hour closure.
The reduced need for lane closures also provides a carbon reduction benefit with initial assessments indicating that 500 tonnes of carbon emissions have been saved, it is claimed.
Although only 4% of the UK’s motorway network is made of concrete – and only 40km of the M25 – the Connect Plus consortium members say that the Rapid Cure technique could save hundreds of thousands of hours of carriageway closures nationally.
Another knock-on benefit is improved worker safety as they are exposed to live traffic for just a fifth of the previous time.
Rapid Cure concrete was introduced by Connect Plus earlier this year following trials both offsite and on the network. Its implementation involved partnership with supply chain framework partners including Jackson Civil Engineering, Balfour Beatty, Osborne, Skanska, Lafarge Tarmac and Aggregate Industries. Expertise was provided by designer Parsons Brinckerhoff, concrete mix specialist Grace Construction Products and volumetric mix plant suppliers Axtell and PJ Davidson.
Highways Agency asset delivery manager Francis Cluett said: “The Highways Agency welcomes Connect Plus' work to develop this new and innovative method of working which minimises disruption by making closure times shorter. Also we want to see road workers spend less time close to live traffic, supporting our Aiming for Zero strategy to make our network safer for them and road users."
Connect Plus chief executive Tim Jones said: “Motorway closures for the replacement of failed concrete bays are a significant cost to us, our customer and ultimately the road user. We’ve been developing the Rapid Cure concrete innovation over many months and it has enabled us to reduce carriageway closure hours by seven weeks this year alone.
“We can achieve this unique innovation, in part, due to our special supplier framework partnership at Connect Plus which incentivises all of us to work together to find solutions for the benefit of the Highways Agency and road users.”