m5 resurfacing sets the standard for next generation asphalts

Holcim UK, working in partnership with National Highways, has completed one of the first demonstration schemes aligned to the new E21 Stone Mastic Asphalt (SMA) specification - setting a benchmark for the next generation of low-carbon, high-performance road surfacing.

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The M5 J28–30 project marks a significant milestone in the UK’s transition to more durable, lower-emission road infrastructure. Developed through National Highways’ Low Carbon Demonstration Fund, the scheme showcases how collaboration between Holcim UK and its supply chain partners can accelerate innovation from concept to carriageway.

The resurfacing demo uses Holcim’s ProLay Ultra asphalt, an established yet continuously evolving product engineered as a next-generation surfacing solution. 

Holcim’s forward-thinking approach to product development means ProLay Ultra already meets the new National Highways E21 SMA specification, which places greater emphasis on durability, whole-life carbon, and ride quality.

Designed with a carefully balanced aggregate matrix, increased bitumen content, and Polymer Modified Bitumen (PMB), ProLay Ultra achieves a low in-situ void content for enhanced resilience and long-term performance.

As part of this demo, a section of the E21 Stone Mastic Asphalt incorporated graphene, further enhancing the mechanical strength, fatigue resistance, and long-term durability of the surface. This innovation demonstrates Holcim’s commitment to exploring advanced materials that can extend pavement life, reduce maintenance cycles, and support lower-carbon road construction.

The M5 project saw Smooth Ride technology deployed to precisely control surface levels and optimise ride quality, enhancing both performance and driver comfort while reducing future maintenance needs. The system integrates Light Detection and Ranging (LiDAR) mapping and 3D road modelling modelled by Driven International and MK Surveys, which guided precision milling through Topcon and Wirtgen systems operated by Tripod Crest. This meticulous process, coupled with echelon paving, eliminates weak joints and ensures a consistently smooth and durable surface.

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Neil Leake, National Technical Manager for Contracting at Holcim UK, said: “The M5 has provided the perfect opportunity to showcase the next generation of surface performance- a scheme that brings together low-carbon materials, advanced paving technology and all within the new National Highways specification. It’s a demonstration of how technical excellence and collaboration can deliver real change across the UK’s strategic road network.”

Holcim UK’s extensive laboratory trials, including rutting and ageing tests, confirm that ProLay Ultra meets the performance requirements of the new E21 SMA specification. The product will be approved under CC 202 E/21 reinforcing Holcim’s confidence in its readiness for future contract submissions and National Highways adoption.

Building on its proven track record on the A590, A30 Roseworthy, and A30 Shallowater, this latest M5 project demonstrates how Holcim UK continues to lead the evolution of sustainable road construction. Helping deliver roads you can rely on, now and into the future.

As the sustainable and technical experts behind many of the UK’s most progressive highways projects, Holcim UK continues to drive knowledge-sharing across the sector. In November, the company will host an in-depth training session on the MCHW specification changes, led by its Technical Director, Phil Sabin, supporting industry partners to prepare for the next era of road infrastructure delivery.