How MacRebur is scaling a circular manufacturing model

MacRebur is attempting something many Scottish innovators struggle to achieve by turning a materials science idea into repeatable, infrastructure-grade manufacturing at scale.

MacRebur

Founded by Toby McCartney alongside Nick Burnett and Gordon Reid, the Lockerbie business has developed polymer additives made from waste plastics that partially replace bitumen in asphalt.

The proposition is straightforward in its aim to reduce landfill and fossil fuel dependency while improving road durability.

The journey, however, has been anything but simple.

Moving from concept to credible supplier required nearly 18 months of R&D, polymer testing and process refinement.

The greater hurdle was not technical feasibility but acceptance.

Highways engineers and local authorities demanded proof that “plastic roads” were not a gimmick but a standards-compliant material capable of performing in harsh conditions.

MacRebur responded with laboratory validation, independent trials and monitored pilot projects.

Its polymers are designed to fully melt and bind within the asphalt matrix, avoiding loose particles or microplastics.

Crucially, the product integrates into existing asphalt plants and laying processes, lowering adoption barriers.

The company has since expanded beyond the UK, with projects across the Gulf region, North America and parts of Europe.

Its commercial model combines additive supply, licensing and technical support, allowing international scalability without replicating full manufacturing facilities in every territory.

As with many clean-tech manufacturers, growth has required reinvestment rather than short-term profit extraction.

Early funding came from founder capital and small loans before attracting private investors aligned with both commercial return and environmental impact.

The next phase is less about proof and more about scale by embedding polymer-modified asphalt into mainstream procurement frameworks and infrastructure planning.

For Scotland’s industrial strategy, MacRebur offers a case study in what scaling actually requires through technical credibility, patient capital, regulatory navigation and international market development.

Q&A: Toby McCartney, co-founder of MacRebur

How did the idea originate?

The concept emerged after seeing informal plastic-in-road repairs in India and recognising the scale of global plastic waste.

Back in the UK, we asked whether we could apply proper science, testing and manufacturing discipline to turn waste polymers into a viable asphalt additive.

After 18 months of R&D and multiple failed trials, we developed formulations that met engineering standards and gave us confidence to commercialise.

What has been the biggest barrier to growth?

Credibility. Infrastructure clients cannot take risks.

We had to prove that our polymers would fully bind into the bitumen, meet safety standards and perform long term.

That meant independent trials, detailed data and transparency. Funding an R&D-heavy venture while building that evidence base was challenging, particularly before we had recurring revenues.

How does the product compare environmentally?

Our polymers replace part of the bitumen binder, reducing reliance on virgin fossil fuels while diverting specific waste plastics from landfill or incineration.

Because the material is fully integrated into the asphalt mix, it does not create loose microplastics. Importantly, adoption does not require new plants or machinery, making decarbonisation incremental rather than disruptive.

Where are you now in the growth journey?

We are beyond experimentation and into repeat projects across multiple regions. International demand is strong, particularly in markets investing heavily in infrastructure.

The focus now is on scaling through licensing and strategic partnerships while continuing to invest in innovation and product development.

Can better materials solve the pothole crisis?

No single product can eliminate potholes, which are typically caused by poor drainage, traffic loading and delayed maintenance.

However, improved materials are part of the solution.

Polymer-modified asphalt can enhance resistance to cracking and deformation, particularly under heavy traffic and freeze-thaw cycles.

Extending surface life reduces lifecycle maintenance costs and disruption.

For local authorities operating under budget pressure, the decision often comes down to short-term cost versus long-term durability.

MacRebur argues that integrating performance-enhancing additives within existing asphalt processes offers incremental gains without overhauling procurement systems.

Ultimately, addressing the pothole problem requires coordinated planning, funding discipline and materials innovation.

Polymer modification represents one lever within a broader asset management strategy.

Scaling beyond experiment

MacRebur began as a small founding team and has evolved into a growth-stage manufacturing business spanning R&D, operations and commercial roles.

Revenues are generated through additive supply, licensing and technical consultancy.

Like many infrastructure-focused innovators, the firm has prioritised reinvestment over immediate profitability, channeling capital into international expansion and further product development.

Its ambition is to embed polymer-modified asphalt as a mainstream specification choice, increasing the volume of waste plastics diverted into long-life infrastructure.

Achieving that requires not only innovation but alignment with procurement frameworks, capital providers and public-sector planning cycles.