Other research projects available in the future, as undergraduate projects, Masters by Research or PhD thesis include:

In additional to the continuation of 2020 research projects, new projects for 2021 include:

Sustainable airport pavements.

Completed as a PhD under scholarship, providing an app‐based calculator of the social, financial and environmental cost of options.

Crumbed rubber modified bitumen for asphalt surface anti‐ageing.

A Masters research project undertaken by Andy Kidd.

Comparison of bituminous pavement surfaces for regional airports.

Undertaken by Dr. Greg White and considering thin asphalt, sprayed seals and microsurfacing.

Asphalt preservation trials.

Undertaken by Dr. Greg White, with the assistance of the Department of Defence, considering various product types.

Simulating arctic snow sintering in a freezer trailer.

A final year engineering project to replicate arctic snow in a trailer mounted freezer on the Sunshine Coast.

Better waste plastic modified bitumen storage stability.

Undertaken by Dr. Ali Jamshidi, considering chemicals called RET and PPA to reduce segregation risk during hot transportation.

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REFLECTION CRACKING OF CONCRETE PAVEMENT JOINTS THROUGH ASPHALT OVERLAYS (ONGOING)

Undertaken by Sahar Deilami (part‐time PhD student) under the supervision of Dr. Greg White and Associate Professor Christophe Gerber.This project aims to develop a laboratory test machine and protocol for measuring the propagation rate of reflection cracks from concrete joints through asphalt overlays. Once developed, the test machine will enable the efficacy and cost‐effectiveness of different asphalt mixtures, strain alleviating membranes and geofabric interlayers to be objectively measured. Initial results are expected in 2021 and completion is expected in 2023.

EVALUATION OF MARGINAL MATERIALS FOR FOAMED BITUMEN BASE COURSE (ONGOING)

Undertaken by Roberto Espinosa (Master of Science in Civil Engineering) under the supervision of Dr. Greg White and Dr. Adrian McCallum.The project considers the efficacy and efficiency of foamed bitumen stabilisation of marginal gravel materials. The general approach includes comparing marginal materials, improved by blending with RAP and other products, to a class A gravel. Improved performance associated with alternate foaming agents is also being considered.Outcomes will improve the understanding of this useful technology for regional and remote airports. Roberto completed his research in 2020 and some outcomes have been published.

PREDICTING AGE‐RELATED ASPHALT EROSION AND RAVELLING FOR AIRPORT ASPHALT MIXTURES

Undertaken by Ahmed Abouelsaad (PhD student) on scholarship under the supervision of Dr. Greg White and Dr. Adrian McCallum. This project will investigate theoretical modelling and laboratory testing of asphalt ravelling, the primary distress triggering runway resurfacing when major distresses (such as severe cracking and groove closure) are avoided. The outcome is expected to provide an objective basis for comparing different asphalt mixtures on the basis of relative erosion and ravelling resistance. Ahmed is full‐time and the findings of this project are expected to become available from 2020 to 2022.

LOAD TRANSFER AND JOINT STIFFNESS FOR RIGID AIRPORT PAVEMENTS

Undertaken by Sean Jamieson (part‐time PhD student) under the supervision of Dr. Greg White and Dr. Ali Jamshidi. This project investigates jointing systems in rigid airport pavements and the factors that affect joint stiffness and load transfer. This will enable a better understanding of joint function and whether current Australian jointing practices are as effective and efficient as they can be. Outcomes are expected to be published from 2021 and completion is expected around 2025.

RECYCLED WASTE PLASTIC MODIFICATION OF ASPHALT BINDER AS A MATURE TECHNOLOGY

Undertaken by Finn Hall (Master of Science in Civil Engineering) under the supervision of Dr. Greg White and Dr. Adrian McCallum. Although significant work has been undertaken to show the improvement in the engineering properties of inders and asphalt mixtures modified with waste plastic, there remains questions regarding the long‐term performance, whether wet mixing or dry mixing is preferable, as well as a range of environmental and safety questions. This project aims to address these issues as well as demonstrating a micro‐circular economy via a real life case study where this technology is being applied.

COMPACTION AND PROVING GRANULAR LAYERS IN AIRFIELD PAVEMENT CONSTRUCTION

Undertaken by Hudson Anstee (Master of Science in Civil Engineering) under the supervision of Dr. Greg White and Dr. Adrian McCallum. This project aims to address the gaps in compacting and proving granular layers for flexible airport pavement construction that were created by the downgrading of the heavy roller fleet, as well as by the ever‐increasing wheel loads and tyre pressures associated with modern aircraft. The project will quantify the current size of
the compaction/proving gap, potential approaches to reducing or closing the gap and will combine field trials with theoretical modelling of roller compactive effort at depth, focusing on vibrating and impact rollers that claim to have similar compactive effort but with a much smaller roller. Outcomes are expected in 2021 and 2022.

ESTIMATING THE REPLACEMENT VALUE AND MAINTENANCE COST OF AUSTRALIAN AIRPORT PAVEMENTS

Undertaken by Jacob Farrelly (undergraduate civil engineering student) under the supervision of Dr. Greg White. This project quantifies the physical area of rigid and flexible aircraft pavement assets across Australia’s 350 (or so) paved and registered airfields, ranging in size from Sydney to Bourke, using GIS‐based tools. Based on typical using aircraft and subgrade conditions, the thickness and cost of the airport pavement asset base will be estimated. Finally, the depreciation cost and maintenance burden associated with Australia’s airport pavements will be estimated. The output will assist engineers and assets owners to seek support for research, development and maintenance funding.

USING CONSTRUCTION RECORDS TO ESTIMATE THE REAL STRENGTH OF AIRCRAFT PAVEMENTS

Undertaken by Rodrigo Lourenco (undergraduate civil engineering student) under the supervision of Dr. Greg White. This project will determine the realistic post‐construction strength of the new Sunshine Coast airport runway pavement based on actual construction data. This will be compared to the designed strength of the pavement using stochastic inputs and Monte Carlo simulations. The output will show that pavements are designed conservatively and are often built with significantly greater strength than was intended by the design.

MODELLING THE MID TERM FRICTION EVOLUTION OF RUNWAYS

Undertaken by Jonard Erro (undergraduate civil engineering student) under the supervision of Dr. Greg White. This project develops a generic evolution of runway friction over the medium term of the 10‐12 year expected life of an asphalt runway surface. Friction survey data was obtained from various airports, where it has been collected multiple times per year over many years, and trends within airports and across airports are investigated. The output helps airports to better understand and manage runway friction over the life cycle of their asphalt runway surfaces.

PILOT PROJECT VERIFICATION OF STONE MASTIC ASPHALT AS AN UNGROOVED RUNWAY SURFACE

Undertaken by Dr. Greg White. Following the development of a specification for stone mastic as an ungrooved runway surface material, this project aims to verify the performance of stone mastic from the pilot project at Emerald airport which was resurfaced in late 2019. The construction quality records, visual condition evaluation and ongoing surface texture/friction testing will allow the efficacy of ungrooved stone mastic to be compared to grooved dense graded asphalt as a runway surface for the future. Comparative costs, risks and construction limitations will also be considered.

COMPARING DIFFERENT MEASURES OF ASPHALT MODULUS

Undertaken by Dr. Ali Jamshidi. This project aims to mine the data from various previous projects where different measures of modulus have been measured in order to develop general relationships between the different test methods. The developed relationships will be compared to theoretical and published conversions to determine their efficacy. A reliable conversion would allow designers to characterise asphalt modulus by the most convenient test method, rather than one that best replicates in‐service loading conditions.

THEORETICAL COMPARISON OF MORE SUSTAINABLE AIRPORT ASPHALT MIXTURES

Undertaken by Demi Van Den Heuvel, a CPEE Master of Pavements student completing an industry research project under the supervision of Dr. Greg White. This project compared the theoretical financial, social and environment cost/benefit associated with the incorporation of recycled plastic, recycled asphalt, crumb tyre rubber and crushed recycled glass in asphalt mixtures. The triple bottom line was used to combine the costs, resulting in a weighted combined or total
cost. The outcome will be published in 2021.

SYNTHETIC AND EPOXY MODIFIED BINDERS FOR AIRPORT ASPHALT PRODUCTION

Undertaken by Dr. Ali Jamshidi A detailed desk‐top review as a first‐cut screen of the potential to modify or replace bitumen in asphalt production with a synthetic or epoxy‐type material. The potential is a surface that lasts 40 years
and it not affected by fuel or high temperatures. The challenges include the high cost of the epoxy materials, as well as the logistics and construction risks associated with products that chemically cure and can’t be softened by reheating.

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The following student and staff projects will commence in 2019, either directly under, or associated with, the APRP.

COMPARING FOAMED BITUMEN BASE PROPERTIES FOR DIFFERENT PRODUCTION METHODS

Undertaken by Tom Weir (Master of Science in Civil Engineering) under the supervision of Dr. Greg White and Dr. Adrian McCallum. The project will compare foamed bitumen-based products produced in the field and in the laboratory, as well as both field and laboratory curing of samples. The results will provide a better understanding regarding the selection of material modulus values for pavement design, based on laboratory mixture design results.Tom is full-time at USC in 2019 and the findings of this project are expected to be available towards the end of 2019 and early in 2020.

EVALUATION OF MARGINAL MATERIALS FOR FOAMED BITUMEN BASE COURSE

Undertaken by Roberto Espinosa (Master of Science in Civil Engineering) under the supervision of Dr. Greg White and Dr. Adrian McCallum. The project will consider the efficacy and efficiency of foamed bitumen stabilisation of marginal gravel materials. Outcomes will improve the understanding of this useful technology for regional and remote airports, with outcomes expected in 2020 and 2021.

RE-SETTING CONSTRUCTION TOLERANCES FOR AIRPORT ASPHALT PRODUCTION AND CONSTRUCTION

Undertaken by Dr. Greg White. Following completion of three airport overlay projects under the Performance Based Airport Asphalt Specification published by AAPA in 2018, the production and construction quality testing results will be statistically analysed to determine the realistic production and construction compliance tolerances. Statistically reasonable limits will then be incorporated into a revision of the specification. In parallel, guidance material will be prepared for the acceptance or rejection of non-compliant materials and construction, based on fitness for purposes evaluations where they are available.

PREDICTING THE RAVELLING RESISTANCE OF AIRPORT ASPHALT MIXTURES

Undertaken by Ahmed Naguib (PhD student) on scholarship under the supervision of Dr. Greg White and Dr. Adrian McCallum.This project will investigate theoretical modelling and laboratory testing of asphalt ravelling, the primary distress triggering runway resurfacing when major distresses (such as severe cracking and groove closure) are avoided. The outcome is expected to provide an objective basis for comparing different asphalt mixtures on the basis of relative erosion and ravelling resistance. Ahmed is full-time in 2019 and the findings of this project are expected to become available from 2020 to 2022.

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UNGROOVED STONE MASTIC ASPHALT FOR RUNWAY SURFACING

Undertaken by Sean Jamieson (Master of Science in Civil Engineering) under the supervision of Dr. Greg White and Dr. Adrian McCallum. This project is adapting the composition of Stone Mastic Asphalt (SMA) used on Australian roads, as well as overseas airports, and will develop an Australian airport SMA specification within a performance-based framework. A number of ‘typical’ mixtures have been designed, produced and tested with the support of the asphalt industry (AAPA members) to validate the mixture design requirements. An airport asphalt resurfacing project has been identified to include a small field trial for future evaluation. Sean is full-time at USC in 2018 and the findings of this project are expected to be presented in 2019.

REFLECTION CRACKING OF CONCRETE PAVEMENT JOINTS THROUGH ASPHALT OVERLAYS

Undertaken by Sahar Deilami (part-time PhD student) under the supervision of Dr. Greg White and Associate Professor Christophe Gerber.This project aims to develop a laboratory test machine and protocol for measuring the propagation rate of reflection cracks from concrete joints through asphalt overlays. Once developed, the test machine will enable the efficacy and cost-effectiveness to be determined for different asphalt mixtures, strain alleviating membranes and geofabric interlayers. Initial results are expected in 2020 and completion is expected in 2022.

COMPARING LAYERED ELASTIC AND FINITE ELEMENT AIRPORT PAVEMENT RESPONSES

Undertaken by Lincoln Johnson (undergraduate Civil Engineering student) under the supervision of Dr. Greg White and in collaboration with researchers from the University of Illinois, Chicago, USA. This project extends the work undertaken by Warren Smith in 2016, with the aim of determining when layered elastic tools are adequate for airport pavement structural analysis and when the additional benefit of finite element tools is warranted. The research includes comparison of finite element model (ABAQUS) calculated pavement response to aircraft loads with equivalent layered elastic model calculated responses, using the Australian design tool (APSDS).

REPEATABILITY OF FWD RESULTS FOR AIRPORT PAVEMENTS

Undertaken by Joshua Beehag (undergraduate Civil Engineering student) under the supervision of Dr. Greg White and building on the work by Andrew Barbeler in 2017.Using a database of results from different FWD machines repeatedly operated over a FAA test pavement, constructed to be as uniform as possible, the repeatability and reliability of key FWD responses will be evaluated. The typical and extreme outliers will be used to calculate layer modulus values and resulting PCNs using the ELMOD software. This will allow the effect of the test variability on pavement strength rating to be determined, as an indicator of the efficacy of relying solely on FWD test results for PCN calculation.

EFFICACY OF NON-DESTRUCTIVE TESTING IN LIEU OF CORING FOR AIRPORT ASPHALT DENSITY

Undertaken by Dr. Greg White. This project explores the use of a non-nuclear density gauge used throughout an asphalt overlay project. The aim is to determine whether the gauge, after calibration and validation, can be used to either reduce or completely replace the need for destructive coring for airport asphalt construction density testing and acceptance. The limitations of the gauge for reliable density evaluation are also considered.

RECYCLED PLASTIC MODIFIED AND EXTENDED BITUMINOUS BINDERS FOR ASPHALT PRODUCTION

Undertaken by Connor Magee (undergraduate Civil Engineering student) under the supervision of Dr. Greg White and with the support of Brisbane City Council, Fulton Hogan, Boral Asphalt and MacRebur.This project aims to evaluate asphalt manufactured with different waste plastic for the extension and modification of bituminous binder. The work combines laboratory bitumen testing, laboratory asphalt testing, asphalt production consistency and a field trial in the northern suburbs of Brisbane.

COMPARING RIGID AND FLEXIBLE AIRPORT PAVEMENT THICKNESSES CALCULATED WITH DIFFERENT DESIGN TOOLS FROM AUSTRALIA AND THE USA

Undertaken by Reeve Balestra (undergraduate Civil Engineering student) under the supervision of Dr. Greg White.This project aims to quantify the differences in pavement thickness required by the USA’s COMFAA, FAARFIELD 1.3, FAARFIELD 1.4 and the Australian APSDS, for both rigid and flexible pavements on a range of subgrades and for a range of commercial aircraft. This will better inform airports regarding the cost implications associated with selecting one software over another.

COMPARING AUSTRALIAN-STYLE FLEXIBLE AIRPORT PAVEMENT THICKNESSES TO FULL-DEPTH ASPHALT AND OTHER PAVEMENT COMPOSITIONS

Undertaken by Georgia Kelly (undergraduate Civil Engineering student) under the supervision of Dr. Greg White. This project aims to analyse the financial cost and environmental impact of Australia’s traditional thin asphalt over thick crushed rock style flexible airport pavements, compared to USA FAA style pavements, full-depth asphalt and full-depth asphalt including EME (high modulus asphalt). The results will better inform designers regarding the implications associated with the traditional and alternate pavement compositions of equivalent structural capacity.

QUANTIFYING THE IMPACT OF RECLAIMED ASPHALT PAVEMENT ON AIRPORT ASPHALT

Undertaken by Dr. Greg White.This project aims to quantify the impact of RAP on airport asphalt performance by comparing otherwise identical asphalt mixtures, with RAP and without RAP, in the laboratory and in the field. Different RAP sources, including the low risk ramps from the same job and existing surface millings, are both being considered.

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