St Helens Borough Council have committed to achieving Net Zero by 2040 and are making continuous efforts to reduce carbon emissions in their borough. The Highways and Infrastructure team elected to partner with Miles Macadam, a carbon neutral organisation, to utilise their reduced carbon asphalt surfacing material Milepave™ on concrete carriageways and address repeated failure issues.
Moss Bank is a large housing estate situated to the north of St Helens Borough and has a significant number of concrete carriageways. For several years, these had been overlaid with conventional surfacing materials and were showing clear signs of deterioration. Miles Macadam’s Milepave™ and concrete system, was specified and installed, starting with the channel planing of the carriageway to remove the existing failed surface and negate the need to adjust kerb and footway heights. The joints and cracks within the exposed concrete were cleaned with a pressurized heat lance and sealed to further eliminate water ingression. A hot bond coat was applied to ensure good adhesion and the Milepave™ Asphalt Grouted Macadam was laid. This consists of a paver laid open graded asphalt receiving course, sealed with a liquid asphalt grout. Milepave’s benefit is that once sealed, it is impervious to water ingress as the asphalt grout seals the surface from the top down. This reinforces surface strength and enhances the flexibility of the material to withstand the thermal expansion and contraction of the concrete base below. Finally, an inducement joint is formed and sealed in the new Milepave™ surface directly above the concrete expansion joints, as a further safeguard against reflective cracking.
The Moss Bank scheme involved surfacing over 10,000m2 of concrete carriageways and has been delivered as an accredited carbon neutral surfacing scheme making it the first of its kind within the Liverpool City Region. By using Milepave™ over a conventional asphalt material, St Helens MBC were able to save over 30 tonnes of carbon. Milepave™ by design is a low carbon surfacing material utilising less aggregate, bitumen and energy during the manufacturing process to achieve a 40% carbon saving over conventional asphalt. Milepave™ has a track record of successful use on both rigid and flexible carriageways, spanning three decades and is a BBA HAPAS approved asphalt surfacing material offering enhanced performance and environmental savings.
The other facet of the scheme with St Helens, covered high stress sites and the utilisation of Miles Macadam’s Cementitious Grouted Macadam, Hardipave™. Two sites were put forward, Millfield Lane Roundabout, located on Haydock Industrial Estate that serves as an access point to over 100 businesses, including several large distribution centres. The other, Westfield Street, in the town of St Helens serves town centre bus and taxi traffic. Both sites were in constant use by high volumes of heavy traffic and the existing HRA surfacing was displaying a significant amount of stress cracking, deformation, and rutting.
With intense traffic loadings, roundabouts and carriageways are prone to accelerated wear. Conventional surfacing materials tend to deteriorate well before their design life with the failure of laying joints and rutting from stationary buses being particularly prevalent. Hardipave™ is an ideal solution for HGV operations and bus traffic as it is designed to have a strong resistance to deformation and abrasion, as well as high tolerance to fuel contamination. Hardipave’s grouting procedure provides a seamless surface course to eliminate any issues with failure and ensures a long-lasting surface course.
Toby Fitzsimmons from Miles Macadam commented on the success of the scheme: “St Helens MBC have a clear commitment to become net zero by 2040. Miles Macadam is delighted to support them through their Highways team with this ambition, by delivering our low carbon Milepave™ surfacing material within the Borough, as the first ‘carbon neutral surfacing scheme’ within the Liverpool City region”.
A link to this article can also be found on HighwaysIndustry.com as part of Miles Macadam’s collaboration with the organisation, click below:
Miles Macadam delivers first local authority carbon neutral surfacing scheme in Liverpool City Region