Stabilised Pavements of Australia - The Experts in Road Recycling

Pavement Recycling and Insitu Stabilisation

Road recycling is a process that has been widely adopted for rehabilitation of road assets throughout the pavement industry for over 60 years. Road recycling is not only a cost effective process but generally offers construction time savings and sustainable solutions.

Environmental benefits of road recycling often include the following aspects:

  • Significant reduction in the use of virgin quarry materials
  • Minimal generation of construction waste through the reuse of existing insitu material
  • Reduced trucking movements as a result of limited importing or exporting of materials form site
  • Reduction in emissions, energy use and noise due to less trucking movements and shorter construction duration

With one of the largest fleet of stabilisation plant within Australasia, SPA has the ability to provide road recycling solutions in any project environment or material type.

Our engineering staff can assist in developing a suitable investigation and design process to ensure we deliver long term rehabilitation solutions within your assets. Please refer to our section on stabilisation methods below to identify what stabilisation methods may be applicable for your project.

From cement stabilisation in moderately trafficked roads, to the use of foamed bitumen within heavily trafficked pavements, we can provide rehabilitation options for any circumstance. Examples of previous projects encompassing pavement recycling and insitu stabilisation can be found within our projects section of the website.

Pavement Recycling and Insitu Stabilisation Solutions

At SPA, the combination of our experience, engineering skills and range of plant and equipment enables us to service the market with a various stabilisation methods. Drawn from the basis that stabilisation is the process of improving or modifying any soil or pavement material, we are able to offer solutions for all pavement applications.


Insitu stabilisation of basecourse materials is the most commonly used stabilisation method within the pavement industry. Basecourse stabilisation is generally the most cost effective means of rehabilitating low to medium traffic volume pavements and can include the use of nearly all binder types dependent on the characteristics of the host material.
Common binders used for basecourse stabilisation include cement stabilisation through cementitious binders however foamed bitumen is becoming a common treatment option for heavily trafficked roads.

Foamed bitumen

Foamed bitumen is a cost effective solution for medium to heavy traffic environments that feature good quality, well graded granular materials.

Foamed bitumen involves the addition of typically 2.5 – 3.5% foamed bitumen (C170 bitumen foamed by water/air) which coats the granular fines producing a matrix with which to bind the coarse aggregate.
Similar to deep lift asphalt, due to its impervious nature foamed bitumen is ideal for use within climates of high rainfall or where pavement saturation is common.
SPA is proud to have been a market leader in both the reintroduction and development of foamed bitumen within the Australian market since the late 1990’s which extends to plant, pavement investigation, design and works methodology.


Subbase stabilisation is commonly used to improve the strength or permeability of the host material within either pavement rehabilitation or construction applications. Common binders for subbase applications include cement, lime or a blend in conjunction with slag or fly ash.

Basegrade Stabilisation

Basegrade stabilisation is a process used to combine both basecourse and subgrade materials to provide suitable pavement depth where existing pavement layer contains insufficient depth with respect to required structural layer thickness.
Basegrade stabilisation is a process commonly used in local government low to medium trafficked environments and has limitations on both the volume of subgrade material to be incorporated and also the type of subgrade material to be incorporated.
Mix design testing for basegrade stabilisation is highly recommended.


Subgrade stabilisation is most commonly carried out on materials of relatively high plasticity and generally involves the use of lime. Subgrade stabilisation results in significant improvements in CBR strength and will therefore reduce the basecourse or subbase layers within the overall pavement design.
Subgrade stabilisation also results in other benefits which include improvement in material impermeability, development of working platform, improvement of material workability or reduction in plasticity index.
Stabilisation of subgrades is a common solution for improving local materials for earthworks projects including roads, rail, mining, airports, formation improvement and hardstands.

Unsealed Roads

SPA provides solutions for unsealed roads which incorporate either binder or granular stabilisation in order to provide a more cost effective, whole of life cycle solution in comparison to conventional resheet and maintenance grading alternatives.
The use of stabilisation to improve unsealed roads can not only provide strength gain but also protect the pavement during periods of high rainfall to ensure that access and use of the asset is maintained at all times.

Formation Improvement

Improvement of a pavement, building or other civil construction formations is a common solution of applying stabilisation methods to improve insitu materails which result in reduced construction costs for developers and distinct environmental advantages in relation to reduction of virgin materials and generated construction waste.

Enclosed Integrated Spreading System (EISS)

EISS has been developed by SPA to provide a process whereby dust associated with binder spreading and mixing activities is minimised through an enclosed application. SPA has specialised transfer vessels which enable us to provide the purpose built reclaimer/stabiliser with both dry powder binder and water in a single mixing pass with minimal dust which is commonly used within urban areas. Our EISS capability is quality controlled and can be monitored through either the use of trays and scales or the on board load cells to verify binder usage.

Environmental Solutions  

Stabilisation is successfully proven method for treating or encapsulating contaminated materials as an alternative to disposal options to not only reduce costs but limit the use of limited land fill resources. These techniques are commonly used by SPA for examples such as Acid Sulphate Soils or Tar Bound Materials.

Dry Powdered Polymers

Stabilisation with Dry Powdered Polymers is an innovate method for modifying the properties of insitu materials. Dry Powdered Polymers such as ‘PolyRoad’ preserve the dry strength of insitu materials to ensure they maintain strength during periods of high rainfall and subsequent pavement saturation.
The use of Polyroad as a dry powdered polymer has been widely used by SPA in conjunction with the Road and Maritime Services (RMS) in NSW with great results, particularly in marginal, locally won gravels.


Granular stabilisation is a common method used on unbound granular materials which often involves the addition of either just moisture to existing materials, or both additional gravel and moisture. Commonly used for unsealed roads, this solutions improves the grading and natural mechanical interlock of the host material in order to provide an improved CBR for traffic loading.
Granular stabilisation is an effective means of rehabilitating or constructing remote, unsealed roads whereby use of locally won materials and effective utilisation of moisture is of primary concern to ensure cost efficient solutions.

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