Optimising the mechanistic and hydraulic properties in the base course materials for permeable pavement

About this project
 
The growing impermeable surfaces increase runoff, which the urban drainage infrastructures are often unable to handle. This is one of the causes of urban flash flooding, substantial damage to properties and social disruptions. Implementing permeable pavements (PPs) for rainwater retention and reuse can play a crucial role in mitigating stormwater runoff, subsequently reducing the risk of floods and providing a sustainable water source for green infrastructure. Although PPs have been employed for low-traffic pavements, their broader application to a significant fraction of 126,906 km of urban road networks in Australia is possible by combining a mechanistic design capable of accommodating wheel loads in PPs. However, mechanistic design for vehicular wheel loads requires a compacted base course for higher stiffness (measured by the resilient modulus, Mr), which reduces the effectiveness of the hydraulic design. This project proposes to optimise both the mechanistic and hydraulic properties of the base course via extensive laboratory testing of base course materials from all states of Australia to establish relationships between Particle size distribution (PDS) and particle-level mechanistic and hydraulic properties. The results will be used to develop an evolutionary polynomial regression (EPR) model that gives a closed-formed polynomial equation for the industry to select the PSD of the base course for the desired hydraulic and mechanistic properties. 

Therefore, the aims of this study are-

• to characterise a range of base course materials (PSDs, mineralogy and sources) to optimise the combined requirements of permeability and water storage capacity as well as a higher Mr for wheel loads
• develop AI-enhanced EPR model
• implement them in the Australian national-standard software DesignPave v2.0, which was developed by Prof Rahman and Beecham    

Rainfall infiltrates through permeable pavement (PP) into the deeper base course layer for storage and detention. Prof Rahman and Beecham developed DesignPave v2.0 software for PP through 15 years of collaborative research with CMAA. This is now Australian national standard software and currently has 1200+ registered users. Our research showed that rainwater retention in PP and reuse played a crucial role in mitigating stormwater runoff, subsequently reducing the risk of floods. 

The study will address the challenges of urban flash flooding and will contribute to saving millions of dollars due to damages to urban infrastructure. The CoS recognised this and became a partner in this project. Therefore, the proposal addresses one of the nine National Science and Research Priorities, namely: (8) Environmental Change, specifically “2. resilient urban, rural and regional infrastructure.”

What you’ll do 

The project will fill the knowledge gaps for the counter-requirements for hydraulic design (low density and high permeability) and mechanistic design (for high density and Mr). They are:

1. Prediction of mechanistic and hydraulic properties of base course materials from the PSD, mineralogies and sources;
2. Use of AI-enhanced EPR to develop a polynomial relation to predicting optimum mechanistic and hydraulic properties;
3. Implement the selection of optimum base course for PP design in DesignPave v2.0.

The project is expected to produce fundamental development in the permeable pavement research and is expected to be published in the top Q1 journal in the discipline, e.g. Transportation Geotechnics, Materials in Civil Engineering. This will leverage a current industry project as well as a future ARC Linkage grant. 

Engagement: The Concrete Masonry Association Australia (CMAA) and the City of Salisbury (CoS) will be involved in the project. The project will deliver a fit-for-purpose PP for CoS. The PhD student, after graduation, is expected to be one of the leaders in the discipline and pioneering in transferring knowledge in the discipline.

Future Impact: According to Market Research Future, the worldwide market size for permeable pavements was $27.98 billion in 2022 and is exhibiting a compound annual growth rate of 5.10% during the forecasted period of 2023-2030. Although permeable pavement research commenced in the 1990s in Australia, its application is still limited and shares a negligible size of the global market. In alignment with the CMAA’s evolving needs, the outcome of this project is to potentially extend its application to the 126,906 km of urban, local and residential road networks in Australia. The CoS will be the first to adapt these new PP

Where you’ll be based

Sustainable Infrastructure and Resource Management (SIRM)

Professors Rahman and Beecham developed a new design approach combining mechanistic and hydraulics principles for permeable pavements and integrated this into the DesignPave v2.0 software tool. 

Prof. Rahman has been a CI in 25 research projects totalling AUD$5.6 million, including ARC LPs, SA Government grants and forestry projects. Since 2018, he has demonstrated an exceptional publication record both in quantity and quality: an impressive average of 25 articles annually over the last five years and 76% of journal articles have been published in Q1 journals (2024, InCites). He ranked 4th worldwide and 1st in Australia in the discipline’s relevant topic T.516: Sand; Void Ratio (2018-23, SciVal). He has 255 refereed publications with a total of 3,186 citations, and he has an h-index of 35 (Scopus). He has supervised and trained 3 Post-doctoral research associates and 16 PhD students to completion. 

Prof. Beecham is an international expert in nature-based solutions, green infrastructure and water-sensitive urban design and is one of Australia’s pioneering researchers in permeable pavement. The project requires his leadership and policy-making experience in many boards and scientific panels, e.g. a Board Director of Water Research Australia (6 years), The Goyder Institute for Water Research (8 years), Chair of the International Group on Urban Rainfall within the International Water Association (6 years), chair of the Standards Australia Technical Committee CE/24 and a past Corresponding Member of Engineers Australia’s National Water Engineering Committee. Despite having significant academic leadership commitments over the past 15 years, CI Beecham has co-authored 145 journal articles, one book and 11 book chapters, and he has an h-index of 48. He has been the Chief Investigator on seven Australian Research Council Discovery, Linkage and LIEF grants, securing more than $10 million in funding overall. He has also received three international publication awards. Financial Support  

This project is funded for reasonable research expenses. Additionally, a living allowance scholarship of $35,200per annum is available to Australian and New Zealand citizens, and permanent residents of Australia, including permanent humanitarian visa holders. Australian Aboriginal and/or Torres Strait Islander applicants will be eligible to receive an increased stipend rate of $52,352 per annum (2025 rate). A fee-offset or waiver for the standard term of the program is also included. For full terms and benefits of the scholarship please refer to our scholarship information. International applicants are not invited to apply at this time.

Eligibility and Selection 

This project is open to applications from Australian or New Zealand citizens, and Australian permanent residents or permanent humanitarian visa holders. International applicants are not invited to apply at this time.
Applicants must meet the eligibility criteria for entrance into a PhD. 
All applications that meet the eligibility and selection criteria will be considered for this project. A merit selection process will be used to determine the successful candidate.
The successful applicant is expected to study full time, and to be based at our Mawson Lakes Campus in the north of Adelaide. 

Essential Dates 

Applicants are expected to start in a timely fashion upon receipt of an offer. Extended deferral periods are not available. Applications close on Tuesday 22 April 2025.