10 Key Points for the better management of unsealed roads

Did you know that approximately 500,000 km, or 61% of the road network in Australia consists of unsealed roads?

Unsealed roads are generally low-cost, low-volume roads constructed to varying standards with locally sourced materials to meet the needs of the community. Nevertheless, there are several underlying principles common to all gravel paved and formed pavements. These include road geometry, maintenance, structural capacity, and surface treatments. With these factors in mind, how can pavement managers improve management of unsealed roads?

Here are the key points for the better management of unsealed roads:

1. Remove water from the roadside

Ensure road are maintained with 4-6% crossfalls and shaped to a crown on straight sections. Use a suitable table, mitre, and cross drains to so that water is removed from the roadside as soon as possible. Maintain natural waterways by providing adequate size culvert crossings.

2. Provide generous geometric standards

Allow for poor and changing road surface conditions, with low surface friction values, by assigning, wherever necessary, higher geometric standards on horizontal and vertical curves and stopping sight distances.

3. Build a pavement to take heavy loads

Build the road on a stable foundation. Allow for adequate pavement depth by providing room for an estimated future passage of heavy vehicles and make allowances for gravel losses. Source locally available materials, by mechanical stabilisation and compact well.

4. Maintain a good riding surface

Create a road wearing surface that binds together to form a hard crust, often by adding cohesive clay fines compacted to a specific moisture content. This will result in improved ride quality and reduce maintenance and dust emissions.

5. Improve road safety

Carry out regular road safety audits to highlight the potential safety hazards and implement a program of remedial works to address the problems, prioritising based on available resources. Ensure safety is at the top of the list.

6. Maintain roads only when needed

Establish appropriate maintenance and intervention standards and adopt a flexible maintenance program to take into unexpected maintenance needs as they arise.

7. Only seal a road if justified

Roads should only be sealed when properly prepared with adequate design standards, pavement depth and drainage provisions.  Improvements to road assets must consider economic implications using a life cycle approach as well as social, environmental, sustainability and political matters.

8. Look after the environment

Consider the environmental impacts caused by unsealed roads. Address poor maintenance practices and inadequate drainage which could cause significant sediment and erosion problems.

9. Protect your investment

Establish an appropriate road asset management system that consists of regular monitoring of the road network and a systematic approach to the development of a works schedule. This should rectify deficiencies in design, safety, environment, materials, etc., as well as maintaining decent road surface quality.

10. Train staff on a regular basis

Ensure that all staff are kept up to date on the latest practices and new developments that will improve overall safety, operating conditions, and lower maintenance costs.

The infographic below provides a summary of how these factors come together under the 10 guiding principles for better management of unsealed roads.