Mainmark: Innovation extending the life of transport infrastructure

Faced with ageing road assets, constrained budgets, and growing pressure to decarbonise, infrastructure owners are increasingly adopting non-invasive, non-disruptive ground engineering solutions to extend asset life while keeping critical road networks operational during repairs.

Australia’s road and transport networks are under increasing pressure. Ageing assets, growing traffic volumes, and more frequent extreme weather events are stretching maintenance budgets and exposing the limitations of traditional, rebuild-heavy approaches.

Across the sector, asset owners are being asked to deliver more with less, while also reducing environmental impact and keeping people and freight moving. As a result, greater attention is being placed on a fundamental shift in thinking: preserving, strengthening, and supporting existing assets can deliver better whole-of-life outcomes than full reconstruction.

At the intersection of structural and geotechnical engineering, ground improvement and re-levelling technologies are increasingly used to extend the service life of roads, rail, water assets, and other critical infrastructure, whilst engineered lightweight fill solutions are reframing the decommissioning of buried infrastructure.

Rather than replacing distressed assets, these approaches address the root cause of failure by restoring and strengthening the ground beneath them, delivering improved performance with significantly less disruption, lower cost, and reduced embodied carbon.

A shift towards preservation over replacement

For much of the past century, the default response to settlement, cracking, or movement in transport assets has been excavation and reconstruction. While this approach still has a role, it is also highly disruptive, material-intensive, and costly, particularly in urban or high-traffic environments.

Mainmark’s Infrastructure and Mining Manager for Victoria and Tasmania, Anastasia Arestia, sees a clear shift underway across the sector.

“There is a noticeable shift away from striving for engineering perfection, and towards maintenance and asset management “ Arestia says. “It’s about preserving assets where they are safe and serviceable, prolonging their life, and intervening in a way that is fast, non-invasive, and cost-effective.”

By improving ground conditions and re-levelling structures, rather than replacing them, infrastructure owners can often restore performance without the extended closures typically associated with asset renewals.

A key advantage is the ability to return assets to service almost immediately once works are completed. In many cases, roads are closed only while crews are on site, significantly reducing congestion and the broader economic costs of disruption.

Lower-carbon solutions, longer asset life

Sustainability has become a central consideration in infrastructure programs, not only during construction but across the full life cycle of an asset. Extending the service life of existing infrastructure is widely recognised as one of the most effective ways to reduce environmental impact, avoiding the emissions associated with demolition, material disposal, and rebuild.

Mainmark’s ground improvement solutions are designed with this lifecycle approach in mind. Once bound within a soil profile, the materials used are environmentally inert, increasing bearing capacity while protecting surrounding ground conditions and waterways.

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One area where embodied carbon outcomes can be clearly quantified is in the use of foamed concrete. Mainmark’s Terefil® foamed concrete is a lightweight, engineered solution commonly used to fill voids, decommission redundant assets, and replace soft or compressible subgrades, particularly in constrained or difficult-access locations.

By carefully controlling mix designs and site production controls, Mainmark’s engineering and technical teams can tailor foamed concrete solutions to meet specific strength and performance requirements, often achieving the desired outcome with significantly lower embodied carbon than traditional alternatives.

“Lower-density solutions can reduce settlement in surrounding soils while also lowering the embodied carbon of a project,” Arestia says. “It allows us to balance engineering performance with sustainability outcomes”.

Proven technologies, new conversations

While these techniques are relatively new in Australia, they have been in use for decades in the US and European markets, particularly residential and commercial construction. Within transport infrastructure, however, awareness and uptake are still growing.

“Our technologies have been around for more than three decades,” Arestia says. “The products themselves are well established and technically proven. The real difference is our approach and how we apply it to complex infrastructure challenges.”

That approach is grounded in a detailed understanding of soil behaviour, structural loading, and how assets interact with the ground over time. It also relies on close collaboration with asset owners to ensure solutions align with operational, safety, and long-term maintenance requirements.

In one recent project for a regional Victorian council, Mainmark recommended a slip-lining solution with Terefil foamed concrete to pressure fill the annulus, extending the life of a deteriorating culvert whilst providing assurance that the space was effectively filled and future risks reduced. In collaboration with the client and consultant, a design was developed that was practical to install, whilst meeting the needs of local traffic and businesses. This avoided the traditional approach to works of a full open-cut replacement, works were completed off-road, with the roadway requiring only a short single-lane closure to facilitate grouting. As a result, project time and costs were significantly reduced without compromising the quality of the solution.

The culvert continues to meet hydraulic performance requirements, while the road remained largely open throughout construction. Once works were completed, the site was fully reinstated by the civil contractor, minimising disruption to road users and the surrounding community.

From alternative to accepted practice

Local governments and rail operators have been among the strongest adopters of non-invasive repair methods, driven by constrained budgets, high asset utilisation, and increasing public scrutiny around disruption and value for money.

“There has been a very positive response across the sector,” Arestia says. “Much of it comes down to effective communication around alternative solutions. Some of our services sit outside traditional structural design pathways, so a key part of our role is helping to inform and educate the engineering and infrastructure community.”

Education is becoming an increasingly important part of that process.

To support a broader understanding of non-invasive ground improvement techniques, Mainmark is planning a live demonstration at the 2026 Municipal Works Conference, to be held on 18–19 March at Bendigo Showground. The demonstration will show how resin injection can be used to densify soil beneath a structure, restoring support while minimising disruption to surrounding assets.