Maintaining unsealed roads
- Cardinia Shire has 862 kilometres of unsealed roads. This is over half our road network; about the same distance as between Melbourne and Sydney.
- We maintain unsealed roads via our Grading and Maintenance, Resheeting and Drainage Works programs.
- As part of our Summer Preparation and Maintenance Program, we’re putting extra resources this year into selected unsealed roads so they stand up better to the heat this summer.
- We schedule works into a road maintenance schedule based on inspections and the reports you make. Sometimes the schedule needs to change at short notice.
- Drafting the road maintenance schedule is a complex process and takes into account a number of factors. Find out how we schedule roadworks.
- For historical reasons, Cardinia Shire has a lot of unsealed roads. These roads are particularly challenging to maintain.
- Driving on unsealed roads is completely different to driving on sealed roads.
- Unfortunately we can't seal every unsealed road, as much as we would like to, given the high cost of sealing roads.
- We are making some important changes to the way we maintain our road network.
Grading and Maintenance Program
- Our crews carry out works on unsealed roads all year-round.
- We have 6 graders operating across the shire at all times. (An extra grader will be in use this summer as part of our Summer Preparation and Maintenance Program 2019–20).
- We also use a skid steer to do detailed works and some isolated pothole patching as required as well as excavators and backhoes and other equipment to maintain the drains that support our roads.
Repair works we do on unsealed roads
Why we grade roads
Unsealed roads need much more frequent maintenance than sealed roads. They are heavily impacted by weather conditions, increased traffic volumes, and the geography of the land where they’re located.
How we grade roads
We use machinery including graders, water trucks and various types of compaction equipment.
- A grader can remove defects by cutting or ripping the road surface. The pavement material is then mixed and re-formed to the correct shape (cross fall or slope) – this allows water to drain more freely off the road.
- The road is then compacted using a roller.
- During the drier months of the year, a truck adds water to the road pavement to help the materials bind and compact.
How potholes happen
Potholes can develop quickly where the road pavement is softened, particularly when water has soaked into the road.
What action we take
To remove potholes we either grade the road, or manually fill potholes with gravel. We generally only do this to fix isolated potholes.
How corrugations form
- Corrugations form when road materials move. They are far more common during dry, warm weather when materials are easily loosened due to a lack of moisture.
- Corrugations can form within days of roads being graded when the roads are very dry.
- Roads with more traffic and higher speed limits are more prone to corrugations.
- Intersections, corners and hills are more likely to form corrugations due to frequent acceleration and braking. Accelerating and braking more gently helps preserve our roads, and is safer.
What action we take
Corrugations are removed by using a grader to cut and blend the existing pavement material. The road is then compacted to form a tightly bound surface. Water is added if needed to help the compaction.
How road narrowing happens
This usually happens on roads that don’t get a lot of traffic, as vehicles tend to drive on a single central lane. As a result, the road edges slowly creep inwards due to vegetation growth.
What action we take
A grader is used to restore the road’s width. If there is a lot of vegetation to remove, a solution is applied to break it up. Any vegetation left on the road after these works will soon break down, and is not dangerous to motorists.
How excess dust forms
- Dust can be an issue in dry weather. It results when the fine particles in the road are stirred up by vehicles. High winds can also create dust.
- Loss of fine particles weakens the composition of the road pavement mix, makes it less compact and causes loose gravel.
- The more vehicles that drive on the road, the more dust that's emitted.
What action we take
- Grading roads helps to keep them tightly bound and compacted. Regardless of this work, hot and dry weather and high speeds can often create dust on unsealed roads.
- Twice a year, around December and February/March, we advertise our resident-funded Dust Suppression Program. Through this program, residents can have dust suppressant applied to their road to reduce dust emissions. Magnesium chloride is sprayed on to the road surface from a tanker. It is usually effective for about 8 to 12 weeks, depending on weather and traffic conditions.
Preparing our roads for summer
Because hot weather is particularly tough on unsealed roads, we’re putting extra resources towards preparing selected unsealed roads across our network for summer.
This heavy work is best done during the cooler months and will help these roads perform better all year round, so we are hard at work on it right now.
Weather permitting, we will comprehensively prepare up to 100 kilometres of the network prior to summer.
This work includes:
- improving the composition of the road pavement. This might involve extracting and blending the existing road pavement materials, or bringing in new materials to achieve a higher quality and more highly compacted finish. It requires lots of equipment, so we usually shut down the road except to local traffic. We apologise for any inconvenience this may cause.
- reshaping the road pavement
- drainage works.
The work will result in roads that:
- stand up better to water on the road surface when it rains
- are more compact and more resistant to defects.
Summer Maintenance Program
This summer we are boosting our grading program by putting an extra grader to work (so there will be 6 graders in total), with staff also working additional hours.
Why we resheet roads
Over time, the crushed rock pavement breaks down due to weather and traffic.
How we resheet roads
- We thoroughly assess the quality and depth of crushed rock on our unsealed road network to develop our road resheeting program.
- Resheeting involves applying 100 millimetres of compacted crushed rock to the road surface.
- Other works that take place in conjunction with resheeting include drainage maintenance and repairing or replacing guide posts, signs and other roadside infrastructure.
Drainage Works Program
Maintaining roadside drains is a core part of our unsealed road maintenance works, as drains have a big impact on the performance of our roads. More info: Drainage works
Why unsealed roads are so challenging to maintain
Dry weather challenges
- Unsealed roads need moisture to bind the materials together. The dryer the weather conditions, the quicker the material comes loose and corrugations form as well as dust..
- If roads become too dry, grading them can sometimes make them worse. If we get a hot, dry summer, a lot of roads can deteriorate at the same time, meaning we have to prioritise works on roads that are most heavily used and in the worst condition. This is what we have done for the last two summers (at the end of 2017 and 2018).
Wet weather challenges
- Heavy or constant rain can cause erosion or damage to unsealed roads, especially where drain infrastructure is limited or the drains get inundated with water.
- Excess water also softens the roads, making them more likely to get potholes.
Why Cardinia Shire has so many unsealed roads
However, our shire is now a mix of rural and metropolitan areas, and we have a fast growing population. This is why we have dedicated $25 million in our 2019-20 budget for the Strategic Sealed Roads Project.
New subdivisions built today usually have sealed roads. The cost of sealed roads, footpaths, drainage and other infrastructure is now shared across all lots to be sold by the developer. The purchaser of the new lot and its subsequent purchasers pay to get the benefits of the infrastructure.
This was not the case for all subdivisions and developments in the past, as requirements were not as strict as they are now.
Why sealing every unsealed road isn’t possible
Approximate cost of sealing a road
- $700,000 per kilometre (rural type road)
- $1.4 million per kilometre (urban type road)
This very high cost means we need to carefully prioritise which roads we seal. You can find out more about our Strategic Sealed Roads Project here.
In special circumstances, residents may be able to pay for their road to be sealed. You can find out more about Special Charge Schemes here.
Driving on unsealed roads
Keep your speed down
- It’s much easier for your tyres to lose traction on an unsealed road than it is on a sealed road, so go easy – this might be much lower than the road’s speed limit, depending on the road conditions.
- Keeping your speed down also helps to reduce dust and damage to the road surface. Please respect our residents along unsealed roads by slowing down to reduce dust.
Go even slower if it’s dusty
Dry weather can create dust and limit how well you can see ahead.
Drive to the conditions of the road
Unsealed road conditions can change quickly and significantly – even within a single day - depending on weather and the amount of traffic on the road. Always obey road signs.
Increase the distance between you and the vehicle in front
The distance it takes to come to a stop on an unsealed road is greater than on a sealed road.
Avoid hard braking, cornering and accelerating
It breaks the road surface apart, and contributes to more corrugations.