Investigation into Scope 3 greenhouse gas emissions of the ACT

Investigators: Thomas Wiedmann (UNSW Sydney) and Manfred Lenzen (The University of Sydney)

Description: Commissioned by the ACT government (Commissioner for Sustainability and the Environment), this study calculated the total carbon footprint of the ACT, including Scope 3 emissions and modelled scenarios to reduce all emissions in line with a 1.5 degree climate change target approach. This is the first time a full international supply chain analysis has been undertaken for final demand in the ACT. A carbon map approach was taken to allow quantification of global origins and destinations of emissions. This study demonstrated the radical changes required by a wealthy Australian city to achieve 1.5 degree compliance, and identifies sectors and supply chains to prioritise to best achieve this outcome.



BHP tailings’ challenge to promote the development of innovative circular economy solution towards eliminating copper tailings

Investigators (repurposing): Taehwan Kim, Iman Al-Damad and Ali Kashani

Description: Commissioned by the ACT government (Commissioner for Sustainability and The Challenge is a new initiative sponsored by BHP that seeks to promote the development of innovative circular economy solutions towards eliminating copper tailings.

Copper tailings are a common by-product of the mineral recovery process and BHP, with the support of Fundacion Chile and its open innovation program EXPANDE, are looking for sustainable economy solutions that can repurpose the tailings into a marketable product by using circular economy strategies. More than 150 teams from 19 different countries put forward proposals, with US$8.6m on offer to the eventual winning solution.

The UNSW-led consortium, which also includes the University of Newcastle, Golder Associates, Maptek, Roobuck, Xilinx, HNTB Corporation and ST Microelectronics, supported by METS Ignited, is led by Professor Sami Kara from the School of Mechanical and Manufacturing Engineering, and co-led from School of Minerals and Energy Resources Engineering by Professors Klaus Regenauer-Lieb and Serkan Saydam.



Decarbonising built environments with hempcrete and green wall technology (ARC Linkage)

Investigators: Arnaud Castel (UTS), Sara Wilkinson, Cecilia Gravina da Rocha, Fraser Torpy, Peter Irga, Taehwan Kim (UNSW), Yixiang Gan, Ailar Hajimohammadi (UNSW), Mahmoud Karimi, Danielle Moreau, Klara Marosszeky and Wil Srubar

Description: This project aims to develop an integrated prefabricated building panel solution combining green wall and hempcrete technology to address environmental problems associated with the usage of carbon intensive construction materials, dense urbanisation, climate change and biodiversity. Innovation in hempcrete technology consists in using low carbon options including alkali-activated binders and biomineralization technology, glass waste replacing natural sand. Hempcrete green wall panels will be designed to be carbon positive, improve the thermal performance of buildings, provide better acoustic insolation, reduce the risk of mould proliferation, control indoor humidity and air quality and improve indoor thermal comfort. The project partners are University of Technology Sydney (lead), University of New South Wales, University of Sydney, Australia Help Masonry Pty Ltd, University of Colorado, Boulder.



Recycling plastic and paperboard waste into value-added asphalt additives (CRC-p)

Investigators: Nasser Khalili, Ailar Hajimohammadi, and Babak Shahbodagh

Description: UNSW, in partnership with State Asphalts, Closed Loop, Primaplas and Asphaltech, will work to convert mixed plastic and paper waste into value-added additives for use in asphalt. The project will aim to recover 3000 tonnes of material per year which would otherwise be exported as waste or landfilled. The partnership received $2.98 million in federal funding through a Cooperative Research Centre Project (CRC-P) grant to develop the technology which will help transform the recycling sector in Australia.


Concrete mixes for durability: a hybrid mathematical optimisation approach (ARC-linkage)

Investigators: Stephen Foster, David Rey and Ailar Hajimohammadi

Description: Reduced service life due to durability problems can lead to considerable negative environmental impacts associated with increased use of natural resources and the resulting increase in carbon emissions and energy use. This project will lead a paradigm shift in concrete mix design methodology, which is currently focused on meeting the mechanical performance objectives of concrete, to a holistic approach that maximises durability of concrete alongside its mechanical performance. The approach is based on a hybrid methodology involving mathematical optimisation of concrete mix based on empirically formulated objective functions for durability properties and mechanical properties.



Next generation sustainable concrete: Trialling recycled glass in geopolymer concrete

Investigators: Ailar Hajimohammadi, Stephen Foster, and Taehwan Kim

Description: Given concrete's significant environmental impacts, there is pressure on the construction industry to source sustainable concrete alternatives that reduce its carbon footprint and finite resource use. This project aims to unlock the potential of geopolymer concrete (GPC) containing recycled glass, as a widespread alternative to Ordinary Portland Cement (OPC)-based concretes. The project, led by John Holland Pty Ltd in partnership with UNSW, Edge Environment and Transport for NSW (TfNSW) will analyse and trial a series of GPC glass mixes on the WestConnex Rozelle Interchange and/or other suitable John Holland Pty Ltd projects, with the aim of contributing to the development of a TfNSW specification for low carbon concrete. This project is sponsored by the Environmental Protection Authority (civil and construction scheme) NSW.


Cost-effective green concrete with recycled glass

Investigators: Ali Kashani, Taehwan Kim, and Stephen Foster

Description: UNSW was engaged by XL IMIX, with sponsorship by the Department of Industry, Science, Energy and Resources, to undertake research in the development of sustainable concrete mix designs with recycled glass for four strength grades of concrete (i.e. 25, 32, 40, and 50 MPa). Recycled glass is used as fine aggregate (instead of virgin coarse sand) and Portland cement replacement. Mechanical and durability requirements, including alkali-silica reaction (ASR) in accordance with Australian (or equivalent international standards) are conducted. A limited life cycle analysis (LCA) will be conducted to quantify the environmental impact of replacing aggregate and cement with recycled glass and compare carbon dioxide equivalent (CO2-eq) emissions of the developed mixes.



Composite columns made of low-grade timber and steel bars

Investigators: Hamid Valipour and Layla Kia (PhD student)

Description: This project aims at combining the cheap low-grade timber available in the domestic construction market with steel bars to develop robust, economical, and structurally efficient hybrid lightweight timber-steel columns and beams with lower energy and carbon footprint than that of the conventional steel and/or reinforced concrete members. The proposed hybrid member fully exploits the high compressive strength and ductility of the timber in conjunction with high strength and ductility of the steel bars to promote greater and more efficient use of the timber in mid-rise buildings and in conjunction with other construction materials.












Long-term behaviour of timber-to-timber composite connections and long-span floors

Investigators: Hamid Valipour and Yatong Nie (PhD student)

Description: Short and long-term deflections are major governing factors in design of lightweight timber and timber composite floors, especially the ones with long spans. In the absence of reliable models required for evaluating the long-term defection of the massive timber-to-timber composite (TTC) floors subject to sustained loads, this project intends to produce benchmark test data and develop and validate analytical tools required for accurate performance assessment of the TTC floors subjected to long-term service load and under an indoor uncontrolled environment.









Insulating sandwich panels

Investigators: Ehab Hamed and Ian Gilbert

Description: With the increasing demands for energy-efficient construction techniques that are driven by global warming and shrinking energy resources worldwide, the use of insulating sandwich panels becomes very attractive and indeed essential in certain cases. The amount of energy required for cooling and heating the interior space of buildings can be substantially reduced when these panels are used, not to mention their other energy-saving advantages in terms of weight and speed of construction. Insulating panels can be comprised of two reinforced concrete layers separated by a layer of lightweight insulation material, which are mainly used as wall panels. They can also be made with thin metal face sheets separated by insulation foam, which can be used in both wall and roof systems. Despite the advantages offered by these panels, there is a hesitancy to some extent to apply them on a vast scale due to lack of design guidelines.  

In a recently funded ARC Discovery project (2016-2018), A/Prof Hamed conducted comprehensive experimental and numerical investigations that provided insight into the structural response of concrete sandwich panels and enhanced confidence in their use. A/Prof Hamed is a member of a number of national and international professional committees, where he is communicating the project outcomes with the aim to provide design recommendations and awareness for such panels. Currently, A/Prof Hamed is conducting research studies on the behaviour of sandwich panels that are made with profiled steel face sheets, aiming to understand their long-term structural response under cyclic temperatures. 




Urban Underground Climate Change Modelling and Monitoring

Investigators: Asal Bidarmaghz

Description: This project will develop a model to, for the first time in Australia, predict and map underground climate change in the presence of current and future underground structures and resources at the city-scale. It addresses a critical challenge for the future of urbanisation: how do we sustainably manage our underground development? The outcomes will be used by practitioners, governments, and environmental agencies, as they (i) plan and design sustainable and resilient underground infrastructure; (ii) exploit geothermal energy resources (iii) develop sustainable solutions for urban groundwater management.



Designing structures for end-of-life deconstructability

Investigators: Scientia Professor Mark Bradford (Australian Laureate Fellow)

Description: An important aspect of designing sustainable building structures is that they should be deconstructable at the end of their service life, to enable the re-use of materials and to eliminate the energy associated with their demolition and disposal. In steel framed buildings with composite flooring systems attached with welded headed stud shear connectors, deconstruction is problematic because of the embedment of the headed studs in the concrete floor. This drawback can be eliminated with the use of bolted shear connectors that join precast concrete slab units to steel joists that are themselves connected to columns using deconstructable bolted joints.

A research programme currently being undertaken at UNSW underpinned by the Australian Laureate Fellowship scheme, is investigating the use of bolted pre-tensioned shear connectors with precast geopolymer concrete slabs. The pre-tension enables a frictional resistance to be mobilised at the steel/concrete interface that enables full shear interaction at service loading, thereby increasing the stiffness of the composite member, as well as allowing for the removal of the bolt in suitably proportioned clearance holes at during the deconstruction phase. A simple mechanical model for representing the service-load behaviour is discussed. At overload, the performance of the shear connection is very ductile, allowing standard plastic design principles to be adopted. The use of deconstructable joints is also discussed, as well as various configurations of precast slabs in the negative moment region of a composite beam adjacent to an internal support.



Non-Structural Applications of Fiber Reinforced Recycled Plastic (FRRP) Aggregates in Roadside Constructions

Investigators: Damith Mohotti, Chi-King Lee, Safat Al-Deen

Description: This research focused on the study and evaluation of the use of more environmentally friendly concrete, containing fibre-reinforced recycled plastic aggregates, for the construction of non-structural roadsides such as kerbs, barriers and concrete walkways. 

The main design parameter considered in designing roadside barriers and kerbs is the ability to withstand the accidental impact of vehicles. Previous experimental results have shown that energy absorbing characteristics of rubber polymer in concrete have significantly reduced the maximum impact force by up to 50% and extended the impact duration. However, the outcome of these studies also highlights the reduction in stiffness or strength of the concrete when used with softer materials such as rubber. 

Therefore, fibre-reinforced recycled plastic shows an excellent potential in replacing the rubber or polymer aggregates by improving the stiffness of the aggregates, enhancing the strength and durability while keeping or enhancing the energy absorption characteristics of recycled aggregate concrete.

Concept of Fibre Reinforced Recycled Plastic (FRRP) Aggregates in Non-structural Applications












Recycling CCA treated timber into wood-cement particleboards

Investigators Amar Khennane and Jong-Leng Liow

Description: The project aims to provide an environmentally acceptable and economically viable solution to the problem of copper chrome arsenate treated timber. The proposal will go beyond materials recycling to product reuse, repurposing, re-design and remanufacturing.

 It will provide an innovative route for decontaminating the treated timber, recovering the heavy metals, and re-using the decontaminated wood in geopolymer cement particleboards for application in buildings. It involves chemical engineering, concrete technology, material science, building energy efficiency, and sustainable solutions for the built environment. 

The technology to be developed will be beneficial to decarbonise the built environment and reduce health risks. Expected outcomes include an economically and environmentally safe re-use for treated timber, environmentally friendly wood cement particleboards, and reduced waste to landfills. 

Wood-cement particleboard used as permanent formwork












Reusing waste plastics in infrastructure projects as construction materials

Investigators: Jianfeng Xue, Amar Kehnnane, Safat Al-Deen

Description: There is a large amount of waste plastic which needs to be processed in local government areas of Australia. It is critical to find solutions that can be adopted easily by local government and industry. The project is in collaboration with local government authority and industry partners under the NESP 2 funding scheme to find solutions for reusing waste plastics as construction materials in infrastructure projects. 



Smart Pavements Australia Research Collaboration Hub: optimisation design of geogrid reinforced asphalt pavement and sinkhole detection under urban pavements.

Investigators: Jianfeng Xue, Amar Khennane, Jing Rao

Description: Due to the presence of soft soils and variation of environmental conditions, the construction and maintenance of road pavements across the world has increased dramatically. With the complicated underground piping and tunnel systems in urban cities, sinkholes often cause failure of pavements and damage to properties. The project includes two major research objectives:

1: to propose a design method to optimize the pavement structure system by including geogrid in the asphalt layer. The research involves laboratory tests, numerical modelling and in-situ tests.

2: To investigate the feasibility of using acoustic detection technology for early detection of sinkholes in urban areas.  



Metro traffic induced settlement of existing tunnel due to undercrossing tunnel, Zhejiang Provincial Institute of Communications Planning, China, 2018-2020

Investigators: Jianfeng Xue 

Description: With the development of urban infrastructure in large coastal cities, an increasing number of tunnels are being constructed. This project aims to study the interaction between upper and undercrossing tunnels in soft soil considering traffic loading induced settlement of tunnels. 

A large number of cyclic loading tests on soft soils have been performed to study the behaviour of soft soils under cyclic loading subjected to different loading paths. Advanced numerical modelling is performed to study the effect on traffic loading induced ground deformation and its impact on tunnel interaction.  



Green high strength ECC: Development and impacts on infrastructure sustainability

Investigators: Chi-King Lee, Sanket Rawat, Yixia (Sarah) Zhang

Description: Concrete is the most widely used construction material in the world, but often suffers from extensive cracking when subjected to tensile stresses which severely affects its durability. Engineered Cementitious Composites (ECC), commonly known as bendable concrete, present a promising solution to this issue as it is possible to simultaneously achieve high compressive strength and tensile ductility. However, excessive use of cement content to satisfy the micromechanics criteria remains one of the concerns in its development. 

Therefore, this project targets the development of a new type of green high strength ECC to shift the focus towards the environmental sustainability aspects, while maintaining adequate resilience for infrastructure applications. The main objective of this project is to minimize the cement content in the development of ECC by replacing it with very high portion of supplementary cementitious materials (such as slag, fly ash) without compromising the compressive and tensile performance. 

Limited life cycle analysis will also be conducted to quantify the impacts of the newly developed composites on environmental sustainability. 



Effect of environmental thermal fatigue and fire exposure on engineered cementitious composite

Investigators: Chi-King Lee, Sanket Rawat, Yixia (Sarah) Zhang

Description: Many areas around the world experience an average temperature of more than 30ºC during summer. The surface temperature of concrete can even reach up to 60-70ºC during this season. Quick cooling of the hot concrete by splashing sea water, rainwater, or rapid temperature decrease during night may cause a sudden reduction in the surface temperature. This phenomenon is known as environmental thermal fatigue (ETF) and may cause degradation in mechanical properties and reduce the service life of structures. In addition, exposure to extremely high temperatures is another area of concern where degradation of mechanical strength is very severe. 


Though Engineered Cementitious Composites (ECC) possess a possible advantage over normal concrete in terms of mechanical performance, it remains unclear whether the use of high volume of industrial by-products in ECC is suitable under fire exposure and the frequently occurring ETF. This project aims towards the evaluation of the mechanical performance of ECC under elevated temperature exposure of up to 1000 ºC. The ECC will also be exposed to thermal cycles of temperatures 20-70ºC to model the situation of an Australian summer. Compression and tensile properties will be analysed to propose a unique composition of ECC which not only consumes very low cement content but can also perform well under both ETF and extreme temperatures.