Aggregate Industries’ New Prolay Asphalt Bridges the Gap on Runcorn’s Silver Jubilee Bridge Renovation

As a Grade II listed structure, Silver Jubilee Bridge spans the river Mersey and connects Runcorn and Widnes. The iconic bridge has been closed since 2017 to undergo a major refurbishment programme.

The revamp of the bridge, led by Halton Borough Council, came with a challenging brief – it required an asphalt solution that could help reduce water ingression, improve durability, and be laid at a minimal 70mm thick over a waterproofing membrane.

Not only that, as vibration on the bridge deck wasn’t permitted, it was essential that the asphalt didn’t require a high degree of compaction. The material needed to be flexible enough to withstand movement; contain low in-situ voids to reduce water ingression through the asphalt onto the bridge deck, while giving good deformation resistance.

Stepping up to the complex task, Aggregate Industries’ Contracting Division looked to its recently-launched Prolay System, a new generation of asphalts offering bespoke solutions tailored to the application.     

Through a consultative approach with Halton Borough Council and multiple site inspections to identify the right-first-time pavement design solution, the contracting team recommended a customised asphalt mix, ProLay Ultra cl.942.

In August 2020, Aggregate Industries’ Contracting Division constructed a 40mm lower layer of very dense and highly rut resistant Hot Rolled Asphalt which was then overlaid with 30mm of ProLay Ultra cl.942 asphalt.

The pavements were laid using state-of-the-art smart surfacing technology to capture the pavement data required to support asset management – giving Halton Borough Council as-built digital data records straight from the paver.

As a great example of Aggregate Industries pioneering ProLay System in action, this project highlights the benefits of early involvement in the design stage to achieve the best results – an approach the client praised.

Ian Jones, Divisional Highways Manager for Halton Borough Council, said: “The design of any bridge deck surfacing can be challenging, but even more so when you only have 70mm of coverage on a Grade II listed bridge. We wanted a solution that could help reduce water ingression, improve durability, be flexible and still give good deformation resistance, all at this minimum inlay thickness.

“Aggregate Industries rose to the challenge and proposed their ProLay Ultra asphalt which ticked all the boxes. With this being manufactured, supplied and laid by Aggregate Industries it gave me more confidence that I was getting the right first time approach."

Paddy Murphy, Managing Director of Contracting at Aggregate Industries, said: “Given the complexity and high-profile nature of this bridge renovation, our new ProLay system of creating a bespoke ProLay Ultra asphalt mix manufactured, supplied and laid by our expert team was utilised on this project. It’s a great example of how this customised approach was able to meet the difficult brief of creating an asphalt solution that didn’t require a high degree of compaction yet still had low voids.”

Aggregate Industries ProLay System offers a new range of exclusive products that contain high grade bitumen that can be mixed at low temperatures to reduce CO₂. Understanding that different problems demand different solutions, the new ProLay System assists clients in identifying the right first time pavement design solution, whilst state-of-the-art smart surfacing technology captures the pavement data, ensuring quality control of manufacture and installation, as well as providing the data required for future asset management.