Better unsealed roads forecast
Those of us who drive on the nations dirt and gravel roads will probably agree with the Australian Local Government Association (ALGA) in welcoming a new Commonwealth Remote Roads Upgrade Pilot Program. This Program will offer councils 80 to 100 percent of required funding to make unsealed local roads safer and more productive.
More than 75 percent of Australia’s road network – about 678,000km in total – is owned and managed by local governments, with 61 percent of these roads being unsealed.
ALGA President Linda Scott commended the Program’s focus on delivering safer roads, saying all councils were committed to minimising road trauma.
“Councils are working hard to keep our communities safe on our roads, as one death is simply one too many,” Cr Scott said.
“We welcome this funding as a positive first step to ensuring our roads are safer, in line with the soon-to-be-announced National Road Safety Strategy 2021-30.”
Cr Scott said ALGA’s 2021 National State of the Assets Report indicated that 14 percent of our unsealed roads are in poor condition.
“The state of local roads across Australia is a major concern, given that the road toll in regional and remote communities is up to 10 times greater than in our major cities,” she said.
“All councils are committed to doing everything we can to ensure our roads keep our communities safe, but this can be a challenging task in remote areas where more financial support from the Commonwealth is needed.”
She said eligible councils would welcome this new opportunity to improve safety, equity, and productivity for their communities – benefits that will also be felt at the national level.
“To ensure no community is left behind, it’s vital that these grants are allocated where they are needed most, with applications assessed against transparent criteria.”
“Local government has a proven track record of working with the Federal Government on road safety programs such as Roads to Recovery and the Black Spot Program, and we look forward to working with them on this new pilot program,” Cr Scott said.
Guidelines for the Remote Roads Upgrade Pilot Program, which will target unsealed roads longer than 20km, are due for release by the end of the year.
Better quality unsealed roads are possible
Normal dirt road surface after rain
As every civil engineer knows, the enemy of unsealed road stability is water. Once water penetrates the surface the end is nigh, with pothole and rut formation soon following. However, preventing water penetration of unsealed surfaces has proved elusive.
A patented system being trial-marketed by Sydney-based Chembase International may change that situation. The system involves the two-stage use of a ’stabiliser’ chemical and an ‘activator’ chemical on a ripped surface, dispensed via a normal water cart spreader bar, followed by grading and rolling.
The water-miscible chemicals react to fill the microscopic spaces between soil particles with a malleable binding compound that is said to prevent water penetrating the surface and destabilising the road structure.
Adjoining Chembase treated road section after the same amount of rain
Chembase says that provided the base soil has at least five-percent clay content, no conventional road base needs to be trucked in.
I inspected a section of test road outside Camden, in NSW, where flooding is common and drainage is limited – a worst-case environment for a dirt road. A section of this road was formed with the Chembase process in late 2020 and the rest of this farm access road was left untreated.
Interface of the Chembase section (top) and the normal road
I timed my visit to coincide with Sydney’s November 2021 drenching and was impressed by the difference between the two road zones. The Chembase road was smooth and undisturbed, but the conventional dirt section was rutted and potholed.
Normal road is wet under the scraped surface
Five-millimetre-deep scrapings revealed that the Chembase section was dry beneath the top surface, while the normal road was wet through. This section of road certainly showed the advantage of the chemical treatment.
Chembase treated surface is wet on top and dry underneath
We’ll monitor progress of this innovation at several other trial sites in NSW and in Queensland over the next few months and report our findings.