Statement attributed to City of Ballarat Director Infrastructure and Environment, Bridget Wetherall
The City of Ballarat acknowledges that a recent road trial on Gillies Road did not deliver the outcome we had hoped for, and we take full responsibility for the result.
In our pursuit of innovative, cost-effective and sustainable road construction methods, we trialled a nanotechnology stabilising agent in the reconstruction of a 1.6km section of Gillies Road, between Jubilee Road and Millers Road, at Bald Hills.
While early testing showed promising results, about six weeks after the completion of the project, the road began to show signs of failure.
After additional investigations we now understand that a key contributing factor to the road failure was our decision to overlay the Terra 3000-treated base with a 100mm conventional crushed rock road base layer.
This approach, while well-intentioned and designed to add depth and strength to the road base layer, is not standard practice in regions where the product has been successfully used for decades.
Investigations found the additional water used during compaction of the top layer was absorbed by the Terra layer below, which had not yet fully cured, ultimately compromising its structural integrity.
This was a mistake, and we are learning from it.
Importantly, we want to make clear that locally based contractor, Fulton Hogan Industries Pty Ltd, which was involved in the project is not at fault. The issues arose from decisions made during the design and specification phase, which were the responsibility of the City of Ballarat.
Prior to the Gillies Road trial, the product had been used successfully in smaller sections of road across the municipality, where it showed promising results. These earlier trials informed our decision to scale up the use of the product on Gillies Road.
Following the first signs of pavement failure in June, we immediately re-engaged geotechnical engineers and the product supplier to investigate.
Testing revealed that the Terra-treated base had reverted to a clay-like state with low compressive strength.
In response, we applied lime stabilisation to the affected sections in late September. We will continue to monitor the road.
Despite this setback, the trial has provided valuable insights.
The nanotechnology product has a strong track record overseas and has shown promise in smaller trials across Ballarat.
Its potential to reduce road construction costs by more than half and deliver stronger pavements remains worth exploring.
The Gillies Road trial cost $970,000 - less than half the estimated $2 million cost of a conventional upgrade.
With nearly $220 million forecast for transport infrastructure renewal across the municipality over the next decade, it is critical that we continue to investigate innovative solutions that deliver long-term value for our community.
For the interim, we will continue with smaller-scale trials to further assess the product's performance.
We remain committed to transparency, continuous improvement and delivering safe, high-quality infrastructure for Ballarat.
