M5 Motorway, UK
Safetrack® Crack Infill reinstates and protects M5 Motorway with minimal lane closure time.
Ageing asphalt surfaces on the M5 are generally in serviceable condition, but like many older asphalt surfaces, are suffering from degradation at the joints between the asphalt mats. As water gets into the joints, hydraulic action and abrasion from vehicles opens up the joint to cause an open or “fretted” joint.
Balfour Beatty and Mott MacDonald (BBMM), who are the sole provider to the Highways Agency of management services for, and maintenance of the motorway network throughout the South West, identified the problem which not only posed a significant safety risk, but also if left untreated, would lead to a substantial breakdown of the surface, ultimately resulting in the need to fully resurface the road.
Balfour Beatty and Mott MacDonald
- M5 Motorway
To extend the pavement life, BBMM opted to take timely preventative action to restore the profile of the asphalt along the joints to provide appropriate skid resistance and to prevent further water ingress, and hence arrest the decay process. As fretted joints are an erosion issue and not related to movement, a high modulus material was required that is both flexible and high modulus like the asphalt itself, to not only reinstate the surface but to protect and support the broken edges of the asphalt surface.
Previous joint repair work on the M5 had seen asphalt locally planed out and reinstated to full depth. However, this process was very time consuming and also created two joints in the carriageways where there had only been one before under the white lines.
As the rest of the asphalt surfaces were generally in good condition, and to avoid disruption from future maintenance activities, a crack and joint repair system with a 5+ year life expectancy was required.
Application Part 1.
Due to the heavy trafficking experienced along this route it was essential that the system used was robust and hard wearing. Safetrack® Crack Infill is based on an advanced, proven durable resin and therefore Balfour Beatty and Mott MacDonald could be confident in the longevity of the reinstatement.
On this project, minimising disruption to the travelling public was a high priority, so a high output repair system was required. Rapid progress for each lane closure also meant that fewer lane closures would be required overall, reducing the cost of traffic management. The machine grade of Safetrack Crack Infill was selected, making this the first machine applied fretted joint repair project in the UK.
This innovative road repair combined Stirling Lloyd’s Safetrack Crack Infill MG product and a revolutionary new machine application process. The lorry-mounted resin extrusion system has been developed to seamlessly repair fretted joints in the carriageways.
Application Part 2.
With laying speeds of up to 3km/h, this automated machine application is safer, more efficient and more cost effective than traditional techniques. All operations are controlled from the truck, meaning operatives in the carriageway for this activity are reduced to zero.
Using this process on the M5, the joint was prepared making sure the joint was clean and dry, then filled and sealed with Safetrack Crack Infill applied in one continuous “one pass” process, with progress being unaffected by inclement weather.
The works had to be carried out over eight night time closures with the road closing at 10pm and having to be reopened to traffic by 6am the following morning, leaving an eight hour window to set out the traffic management, prepare the crack, apply the Safetrack Crack Infill and remove the traffic control.
With minimal preparation required, the simple cleaning and drying of the crack before the Safetrack Crack Infill was applied, combined with the machine application technique and Safetrack Crack Infill’s fast cure enabled approximately 1,000 linear metres per hour to be treated.
The Safetrack Crack Infill MG system is cold applied which means no heating of materials on site. In addition, the rapid cure of the bespoke resin meant that application could continue up to 30 minutes before the traffic management was due to be removed, and the road returned to full traffic load just 30 minutes later.
Following the first installation, Balfour Beatty and Mott MacDonald were so impressed with the performance and the speed of application of Safetrack Crack Infill MG on the first installation of M5 Motorway, they used the same technique and material on a further 100,000 linear meters along the route.