How roads are built
A road is made up of three layers:
The surface – the top level of the road
The pavement – made up of one or more layers of gravel known as the base and sub-base to strengthen the road, and is generally 300-500ml thick
The sub-grade – a natural material beneath the pavement that consists of clay, ironstone and sometimes rock.
How potholes form
Heavy traffic and natural ageing causes cracks in the surface or underlying pavement. Rainwater seeps through these cracks into the base material beneath. The vibration of traffic causes the wet base material to settle or shift, forming a cavity. Without base support, the pavement weakens further and ultimately caves in, causing a pothole.
Potholes are filled with a mixture of asphalt and gravel. Potholes are repaired as a temporary solution in the winter to improve road safety for motorists. Potholes are also repaired as a temporary solution until the road is prioritised for major patching or reconstruction under the capital works program.
What is major patching?
Major patching is used to repair multiple potholes and failures in the road surface and underlying pavement. This is where a larger section of road is removed and both the surface and pavement are replaced. These works require dry weather and are usually carried out in the summer months.
We assess the urgency of maintenance and prioritise the works to be carried out. We engage contractors who specialise in major patching to undertake the works. Each year, major patching is carried out on about 150 roads across the municipality.
What is re-sealing?
Re-sealing is a proactive road maintenance program that works to prevent potholes and small cracks starting to form in the road seal, which allow water to seep into the road pavement. This road reseal program sprays bitumen on to the road surface, providing a new waterproof barrier. Road sealing is carried out every 10 to 15 years to extend the life of our roads. Each year, we reseal about 200 roads across the municipality.
What is roads renewal?
This is the full reconstruction of a road when roads are at the end of their useful life. The tell tail signs of a failing road include wheel lane rutting, potholes and edge breaks. A geotechnical investigation of the old road pavement determines the strength of the road and informs the new design that will ensure the road is built to cater for future demands and traffic loads. Old roads are reconstructed to new standards, usually with a thicker pavement and wider traffic lanes. The shoulders of the roads are also constructed and sealed to prevent edge cracking and provide laneways for cyclists.
How can you keep our roads safe?
The City of Ballarat encourages residents to report any repairs needed to our roads. To request repairs to a City of Ballarat Road, visit forms.ballarat.vic.gov.au/Report issue or call Customer Service on 5320 5500.