The Smarter Way to Build Sustainable Roads in the UK with Recycled Asphalt

A Road to Change

Every year, millions of tonnes of asphalt are removed from UK roads during maintenance and resurfacing works, yet only a fraction of this valuable material makes its way back into new road surfaces. Despite proven performance and clear environmental benefits, recycled asphalt planings (RAP) remain vastly underused across the UK.

Why aren’t we using more recycled asphalt on UK roads, is a question many in the highways and infrastructure sector are asking.

With landmark trials, such as Transport for London’s (TfL) A1 Mill Hill project, showing that asphalt mixes containing 50% recycled material can outperform conventional surfaces even after nearly a decade of wear, the evidence is clear. The technology works and the benefits are measurable. The barriers, however, are systemic.

At Greener Asphalt, our mission is to remove those barriers by making sustainable, zero waste road construction a reality. Our mobile asphalt recycling plants, aggregate dryers, and electric asphalt hot boxes are proving that the future of highways can be both circular and cost effective.

The Case for Recycled Asphalt

Recycled asphalt isn’t new, it’s simply underused. Asphalt planings, often called RAP, are the milled layers of old road surfaces removed during maintenance. These contain valuable bitumen and high quality aggregates that can be reused in new mixes, drastically reducing the need for virgin materials.

The benefits of using higher RAP content are significant

Lower embodied carbon: reducing emissions from quarrying, production, and transport.

Preservation of natural resources: less demand for virgin aggregates and bitumen.

Reduced waste to landfill: promoting a circular economy in road construction.

Cost savings: cutting raw material and disposal costs.

Yet, despite these advantages, the average RAP content in UK asphalt remains far below its potential. According to the European Asphalt Pavement Association, Great Britain produced 22.6 million tonnes of asphalt in 2023, with 5.4 million tonnes of site won asphalt, but only 38% of that material was reincorporated into new road layers.

That means millions of tonnes of reusable asphalt were downcycled or discarded, a huge missed opportunity for decarbonisation.

Proof the Technology Works

The A1 Mill Hill trial by FM Conway for TfL is perhaps the most compelling case study to date. In 2016, a 50% RAP surface was laid on a busy London arterial route. Nine years later, recent testing found that the recycled mix performed as well as, or better than, the traditional mix laid alongside it.

The section using 50% RAP demonstrated:

• Better rutting resistance (1.2mm vs 1.6mm).
• Excellent bonding and water resistance.
• Comparable stiffness and long term durability.

“These findings are significant,” said TfL principal engineer Lukash Manandhar, “as they help shift perceptions of high-RAP asphalt towards being a reliable and durable solution.”

Over the past few years, Greener Asphalt’s own circular recycling projects have shown that high performance road surfaces can be achieved using recycled materials. For example, our 10 Tonne Asphalt Recycling Plant, now operating across the UK, enables contractors to produce high-quality asphalt directly on site using reclaimed planings. By processing and relaying material in a single continuous cycle, the system eliminates waste, transport emissions, and reliance on virgin aggregates.

In one recent application, Greener Asphalt’s mobile recycling technology helped a contractor complete a large scale resurfacing project using 100% recycled asphalt, cutting carbon emissions by over 50% compared to traditional methods. The result wasn’t just environmentally beneficial; it delivered durability, cost savings, and consistent performance equal to conventional mixes.

While Greener Asphalt’s systems are designed to maximise recycling, their flexibility goes far beyond that. Our mobile recycling plants and hot boxes can also produce new asphalt from virgin materials, whether using bagged aggregate and bitumen or reprocessing leftover hotbox waste.

These projects prove that recycled asphalt technology isn’t a compromise, it’s an upgrade. With proper design and temperature control, Greener Asphalt’s equipment delivers robust, compliant materials that stand up to traffic and time, proving that circular road construction is not only viable but essential.

Why Aren’t We Using More Recycled Asphalt on UK Roads?

There are several structural barriers that are holding the industry back.

Modernising Specifications

While current UK highway specifications (The National Highways Manual of Contract Documents for Highway Works) still limit recycled content to 10% in surface courses and 50% in binder and base layers, change is underway. TfL has already paved the way with clauses allowing recycled asphalt planings (RAP) “without an upper limit,” provided performance standards are met; a model Greener Asphalt’s technology is fully equipped to support.

Our systems provide flexibility today, not just when future standards arrive. While legislation continues to evolve, contractors can use Greener Asphalt’s equipment to produce compliant, high quality mixes using both recycled and virgin materials directly on-site or in depots, keeping projects moving while the industry catches up.

Consistency Through Controlled Recycling

Quality variation in recycled asphalt often comes from poor handling, but that’s exactly what Greener Asphalt eliminates. Our onsite recycling systems process materials directly at source, meaning contractors retain full control over temperature, moisture, and material integrity.

Every batch is processed to specification using controlled heat and mixing cycles, producing a consistent, high performing asphalt that meets the same engineering standards as virgin material. In short, we remove the risk of inconsistency and deliver repeatable, testable quality.

Advanced Technology That Removes Plant Limitations

Traditional asphalt plants were never designed for high RAP use, but Greener Asphalt’s mobile and fixed recycling units are. Our technology incorporates parallel heating systems and precision temperature control, ensuring the bitumen binder is rejuvenated, not overheated.

This means contractors can safely produce high-RAP or even 100% recycled mixes without relying on specialist infrastructure. This means zero waste, lower carbon, and no compromise on performance.

A Smarter Economic Model

For many producers, tight margins make innovation seem risky, but we help turn sustainability into savings. By eliminating haulage, landfill fees, and the need for virgin aggregates, our technology creates immediate cost efficiencies while protecting against volatile material prices.

With government and industry moving toward carbon based tender scoring, investing in circular technology is no longer a gamble, it’s a competitive advantage.

Confidence and Collaboration Over Caution

Change in the highways sector often moves slowly, however our proven systems have already helped contractors and local authorities across the UK demonstrate that recycled asphalt performs equal to, if not better than, traditional materials.

By combining reliable data with transparent performance reporting, we’re helping procurement teams move from risk aversion to evidence based decision making, making sustainable choice the easy choice.

Wider Environmental and Economic Impact

The impact of high RAP asphalt extends beyond the carbon footprint of individual projects, it reshapes the economics of road maintenance.

According to industry data:

• Recycling asphalt can reduce embodied carbon emissions by up to 50% per tonne of mix.
• Each tonne of RAP reused saves roughly 60kg of CO₂ and avoids landfill disposal fees.
• Using 50% RAP in just 10% of UK resurfacing projects could save over 250,000 tonnes of CO₂ annually.

Projects using Greener Asphalt’s drying and recycling technology have already demonstrated tangible results:

• £32,000 saved annually in topsoil and aggregate purchases.
• £16,000 saved in logistics costs.
• Thousands of tonnes of carbon avoided by reducing landfill trips and import requirements.

This is the circular economy in action, waste that once drained resources now becomes a source of value, both environmentally and financially.

A Regulatory Shift Is Coming

The withdrawal of outdated regulatory frameworks like RPS 298, and the introduction of the SWUK Material Classification Protocol, marks a turning point for the utilities and highways sectors. These changes demand better waste management, greater accountability, and a move toward circular solutions.

Rather than viewing these regulations as burdens, forward thinking contractors are already using them as a springboard to modernise. Technologies like Greener Asphalt’s mobile recycling systems and aggregate dryers align perfectly with these evolving standards, simplifying compliance while reducing costs and environmental impact.

The transition to circular materials isn’t optional; it’s inevitable. Those organisations who adopt now will be the ones leading when sustainability becomes the baseline expectation.

Collaboration Is Key

No single organisation can deliver this transformation alone. To scale up the use of recycled asphalt across the UK, collaboration is essential; between material suppliers, contractors, plant operators, and local authorities.

Highways England, TfL, and leading contractors have already shown that collaboration leads to progress. When engineering teams, materials scientists, and sustainability experts work together, barriers like testing requirements and plant technology can be overcome through shared knowledge and investment.

At Greener Asphalt, we’re proud to play our part - supplying the tools and technology that make collaboration practical, mobile, and results driven.

Paving the Way Forward

The question isn’t whether recycled asphalt works, it’s how quickly the UK can mainstream it. The benefits are undeniable:

• Sustainability: Dramatically lower carbon emissions.
• Economics: Reduced costs for materials and logistics.
• Performance: Proven durability equal to or exceeding virgin mixes.
• Scalability: With mobile recycling plants, adoption no longer depends on centralised infrastructure.

By rethinking how and where recycling happens, Greener Asphalt Solutions is removing the friction from circular construction. Our mobile plants, dryers, and eco hot boxes are already helping clients cut costs, stay compliant, and meet their sustainability goals, without compromising quality or efficiency. Whether working with recycled planings, virgin materials, or leftover asphalt, Greener Asphalt’s technology gives contractors complete control over their mix, anywhere, anytime.

Time to Rethink the Road Ahead

Nine years of real world testing have proven that recycled asphalt performs. The technology exists and the results are proven. 
The highways of the future should not be built on newly quarried materials and outdated systems, they should be built on innovation, responsibility, and circularity.

At Greener Asphalt, we’re turning that vision into action, enabling contractors to recycle, remix, and reuse asphalt sustainably, whether from existing road planings or fresh materials. If your projects are still sending asphalt to landfill or relying on costly off-site production, it’s time to rethink your approach.

Get in touch with Greener Asphalt today to see how our mobile recycling plants and asphalt mixers can cut your costs, reduce carbon, and future-proof your operations.