PurposeThe construction industry is a major generator of waste, which has a high potential to yield a substantial amount of waste into the economy as a valuable resource. Waste trading (WT) is a sustainable strategy for improving resource utilisation and transitioning the construction industry towards the circular economy. However, resource recovery through WT is greatly impeded by several barriers which have not been highlighted in previous research. This paper aims to determine the barriers for implementing effective WT practices in the Australian construction and demolition (C&D) sector.Design/methodology/approachTo achieve the aim of this research, a triangulation approach of quantitative and qualitative methods has been used. This mixed-method approach combines a comprehensive literature review, a questionnaire survey using an expert forum and semi-structured interviews with industry experts.FindingsThis study has explored a wide range of barriers to the practices of WT in the C&D sector, which have been categorised based on six perspectives. From a collective perspective, the technical barriers were found to be most important among other categories. The key individual barriers found in this study include the following: the high cost associated with sorting and processing of waste on-site, lack of consistent waste data and reporting system at project, industry and national level, insufficient secured and established market for reusable/recycled waste materials, lack of communication and coordination among stakeholders, lack of user-friendly and active web-based waste exchange systems (with reliable waste information) and lack of incentives from the government to encourage market development. Overcoming these barriers collectively would enable the wide application of WT, which in turn, would have a positive impact on the economy, environment and efficiency of the industry.Research limitations/implicationsThe outcomes of this study are based on the data collected only in the state of New South Wales (NSW) in Australia which is considered as the limitation of this study.Originality/valueThis study contributes to the body of knowledge of C&D waste management (WM) by providing the theoretical and practical implications of closing the loop material cycle by highlighting the importance of economic and environmental benefits of WT. In this study, WT has been recognised as a sustainable strategy to manage waste by identifying the barriers impeding the wider application of effective trading practices in the C&D sector. The findings are useful to WM businesses engaged to establish new circular business models and to government/regulatory bodies in developing initiatives and incentives aiming to promote WT strategies and market platforms. Further research is suggested to test and validate the findings from other jurisdictions of Australia.

The procurement system is a key means through which the client creates pre-conditions for successful achievement of project specific objectives. Wrong selection of procurement system generally leads to project failure and client dissatisfaction. Therefore, a systematic and realistic approach for the selection of the best procurement system is critical to the success of any project to achieve the clients' ultimate goals. As far as Sri Lankan construction industry is concerned, the practice of procurement selection is rather unstructured and ad hoc. Therefore, a realistic and consistent approach is essential to aid the clients in selecting the most appropriate procurement system. This paper presents a Decision Support System developed for the procurement selection based on Multi Attribute Utility Technique. Four rounds of Delphi surveys were carried out to investigate the most significant factors and their level of influence on various construction procurement systems. From the third and fourth round of Delphi, utility values for each factor against various procurement systems were derived. Based on decisive factors and the utility values derived form the survey, a multi-criteria model was developed. The special feature of the model is the inclusion of a set of exclusive selection criteria at macro level and wide range of various procurement options. The outcome of the model was evaluated for its applicability and efficiency with the use of multiple case studies and an expert opinion survey. Finally, the evaluated model was further enhanced to a Decision Support System. The model has the potential to assist the clients/their consultants and it seeks to overcome any inconsistency in the effective decision making process. DOI: 10.4038/besl.v7i2.1943 Built-Environment Sri Lanka Vol.7(2) 53-43

PurposeWaste diversion rate (WDR) is a key indicator of effective waste management and circular economy. However, it has not yet been widely used in the construction and demolition waste (C&DW) sector. This study aims to promote the application of WDR as an effective measure for waste management through the investigation of the current status of C&DW diversion in the Australian construction industry.Design/methodology/approachA mixed-method approach, which combines a desk study and a case study of 12 residential projects was used in this study. Data retrieved from the National Waste Database (NWD) were used for the descriptive analysis.FindingsThe analysis of the national waste data revealed that the national average WDR in Australia is 64%. WDR varies based on material types and across the states. The analysis facilitated the forecasting of the possible future trend of waste diversion in Australia. The studied projects from two states in Australia presented slightly different results. Most of the waste stream, except mixed waste, presented above 95% of WDR in each project.Research limitations/implicationsAlthough the studied projects showed a higher recycling rate, this study claims that achieving a higher rate of recovery by diverting the waste could not be assured unless accurate estimation is carried out with reliable and verifiable data. Lack of reliable data is considered as the limitation of this study. While the scope of descriptive analysis of waste generation and diversion covers the whole country, the case study analysis is limited to the states of New South Wales and Victoria.Originality/valueThe study highlights the significance of WDR in assessing the performance of effective waste management in the C&DW sector. WDR is a comprehensive measure that takes the output of the waste life cycle into account for benchmarking waste management. The results provide a critique of the current practices of waste management and the essence of the consistent, transparent and verifiable waste data to enable accurate WDR estimation in Australia. The outcome is useful for waste managers and policymakers in developing potential waste management strategies and C&DW specific legislation for building a more ecologically sustainable industry.

The management of construction and demolition (C&D) waste, a major part of solid waste, is increasingly become a critical challenge in the quest of social, environmental, and economic sustainability. Innovative and smart technologies are emerging to provide inevitable benefits because of their capacity to enable digitisation, automation, and integration of Solid Waste Management (SWM) processes. Nevertheless, the application of such technologies in Construction and Demolition Waste Management (CDWM) has not gained the appropriate attention. This study aims to draw insights into the current and potential use of smart technologies in CDWM. A literature review-based approach surveyed both academic and applied publications to analyse the current and potential use of smart technologies in both SWM and CDWM. Altogether, 75 peer-reviewed articles and technical white papers were analysed. It was found that the usage of smart technologies is much advanced in SWM and the adoption is still at the prototype stage in CDWM. The results emphasise that the integration of smart technologies into multiple processes of CDWM would overcome many issues related to waste minimisation and management including waste estimation, waste reporting, and data management and waste diversion. The framework developed in this study contributes to the understanding of the potential role of each category of technologies in improving the waste management processes in the C&D sector. This review is useful to waste management practitioners, regulatory bodies and the government to understand the benefits of emerging technologies and to the development of effective strategies and future training programmes.

The rapid growth of population and associated urbanization and economic development calls for increased demand for infrastructure development to meet ongoing and future demands. A better understanding of the waste management (WM) processes would help to manage large volumes of waste effectively at construction sites, maximise the value of resources and improve environmental and economic performances. This research aims to investigate the WM processes associated with different types of construction and demolition (C&D) waste generated by a mega infrastructure project through a case study approach, combining expert interviews and project-specific document reviews. The case studied project demonstrated high environmental and economic sustainability outcomes and exceeded the C&D WM targets, signifying more than 90% landfill diversion rates for both spoil and construction waste generated during the construction stage. As such, the infrastructure projects have a great potential to maximise the reuse of high-value waste through waste exchange across projects and gain economic and environmental benefits, while leading to paving a path to greener Australia in near future. The outcome of this case study is a WM process flow diagram (PFD) that maps out the WM processes, waste fates and associated waste flows involved with the diverse range of C&D waste throughout its life cycle. The PFD developed in this study serves as an operational tool to develop effective WM plans for construction projects of similar nature and thus helps to achieve higher landfill diversion rates. The outcome of this study can also contribute to the development of a generic WM PFD for the C&D waste stream.