Pavements on Expansive Soil Subgrades
Tender ID: 602374
Tender Details
Tender Description
Purpose
The purpose of this project is to improve the identification, design, construction, and rehabilitation of pavements built on expansive soils, leading to improved long-term pavement performance.
The project aims to investigate and refine the classification and definition of expansive soils, and to improve the understanding of pavement performance risks associated with expansive soil subgrades.
Scope:
The scope of this project will include two key tasks:
- Improving the identification and classification of expansive soils in relation to the soil’s properties and how the expansive soil impacts the pavement’s performance.
- Document and assess the historical performance of various expansive soil treatments and provide improved guidance on effective treatment options for the design and construction of pavements on these subgrades.
To support these tasks, the project will include:
- A detailed investigation of these materials including zone of influence (also known as the active zone, which refers to the depth within the soil where moisture changes most significantly affect the soil's volume, causing it to swell or shrink), different climate zones, construction placement techniques, the effects of different overlying pavement materials and their permeability variations over time, the impact of trees, and road cross-section design.
- Desktop investigations and analysis of existing field data and observations to support understanding of expansive soil classification, pavement performance and/or the effectiveness of different treatments.
- Review how expansive soils are identified – what are the most appropriate property(ies), what are the most appropriate laboratory test(s), environmental considerations.
- Review how expansive soils affect greenfield pavements and brownfield pavements (rehabilitation):
-how the active zone (zone of influence) of the expansive soil within the pavement formation width varies for different climate zones and pavement types,
-can moisture equilibrium be considered,
-how to maintain moisture equilibrium across the pavement width,
-managing shrink-swell of the expansive soil within the pavement width and associated cracking,
-material selection and use of granular or bound materials.
- Review current state of play internationally and locally.
- Identify and evaluate performance of various pavement designs/treatments applied in black soil country – NSW trial sites; QLD approaches; VIC moisture barriers; SA trials;
- Align the desktop review findings against field observations / soil classifications – evaluate the performance of expansive soil treatments / trials in the field.
- Review treatments/design of culverts to avoid differential movement.
- Development of a decision matrix to select the most suitable expansive soil treatment(s) based on historically effective and proven treatments which considers project-specific inputs.
- Prepare an Austroads research report that is suitable to be used as a basis for a future update to the Austroads Guide to Pavement Technology.
These improvements will increase confidence in pavement design, reduce both under-design and over-design, enhance long-term pavement performance, and minimise maintenance activities and associated costs.
This will save costs in managing the pavement asset, and reduce the impact (for example, delays) on road users caused by pavement defects, failures, and roadworks. Further to this, improved pavement performance (less roughness and cracking) will improve the safety, resilience, and reliability of the road network.
Deliverables:
This project will produce the following final deliverables:
- Research report
- Updated edition of Austroads Guide to Pavement Technology Part 2: Pavement Structural Design (AGPT Part 2)
- Updated edition of Austroads Guide to Pavement Technology Part 5: Pavement Evaluation and Treatment Design (AGPT Part 5)
- A webinar
- Project data with populated metadata spreadsheet.
Location
New South Wales : Central West : Far North Coast : Far West : Hunter : Illawarra : Mid North Coast : Murray : New England : Orana : Riverina : Southern Highlands : Sydney
Queensland : Cairns & Far North Queensland : Gladstone : Mackay Whitsunday Region : Mount Isa & North West Region : Rockhampton : South East Queensland : South West & Darling Downs : The Central West : Townsville : Wide Bay Burnett
Victoria : Barwon South West : Gippsland : Grampians : Hume : Loddon Mallee : Melbourne
South Australia : Adelaide : Eyre & Western : Far North : Fleurieu & Kangaroo Island : Limestone Coast : Murray & Mallee : York & Mid North
Northern Territory : Barkly : Big Rivers : Central Australia : East Arnhem : Greater Darwin : Top End
Australian Capital Territory
Tasmania