Demolition waste generation has grown throughout the years with the urbanization process. The environmental impacts of demolition waste generation and related waste treatment have attracted global attention from the government, industry, and academia. With advancements in building information modelling and life cycle assessment methods, it provides possible solutions to managing demolition waste in a more systematic way.
1. Introduction
The rapid growth of the economy and human population has accelerated urban land resources exploitation by stimulating the large-scale construction and demolition of residential buildings and infrastructure. Those activities, including land excavation, site clearance, roadwork, and building renovation, tend to produce an enormous amount of construction and demolition waste (C&DW)
[1], resulting in heterogeneous environmental problems, such as global warming, natural resource depletion, and land degradation. Moreover, 32% of global resource exploitation and 40% of virgin materials consumption can be attributed to the construction industry
[2]. Under these circumstances, reinventing the entire production and distribution chain and recovering materials under a “cradle to cradle” principle ensures that the construction material flow transfer occurs in a closed-loop
[3]. To this end, improving resource efficiency through systematic C&DWM provides a new perspective that is in line with the sustainable development goals (SDG) and circular economy (CE) principle.
This situation also applies to the Australian construction industry. According to the Australian national waste report
[4], the total amount of waste produced domestically from 2018 to 2019 was approximately 74.1 million tons (Mt), in which C&DW stands out as the primary contributor among diverse waste streams, accounting for 43.9% (27 Mt) of the total core waste generation (61.5 Mt). Of the 27 Mt of C&DW produced in 2018–2019, 23.2% (6.3 Mt) was sent to landfill sites, 76% (20.5 Mt) was recycled domestically, and the rest was incinerated for energy recovery. Over the past 13 years for which data are available, the C&DW stream grew by 61% in total amount and 32% per capita, respectively
[4], with most growth occurring in the last five-year span due to the unprecedented pace of urban development.
From a life cycle perspective, the benefits of C&DW recycling typically triumph over the adverse impacts incurred by waste treatment procedures, which are embodied in reducing the carbon emission and natural resource exploitation related to raw material production
[5]. In this context, industrialized countries (e.g., Australia and Japan) have progressively devoted themselves to maximizing the recycling rate of C&DW materials, comprising masonry, metal, timber, glass, plastic, and hazardous materials
[6]. Pickin et al.
[4] indicated that masonry waste (e.g., bricks, concrete) generated from construction and demolition activities contributes to 73.8% of the C&D waste and 87.7% of the entire masonry waste generation in Australia, respectively. In comparison, metal materials only constitute 2% of the total C&DW; however, they correspond to the highest recycling rate at 90%, owing to the continuously growing market price and demand for metal materials
[7].
Nonetheless, sustainable development within the construction industry comprises inefficient decision-making for reuse and recycling due to inaccurate C&DW quantification with limited data on the building materials and components
[8]. Instead, general practices employ rough calculation methods, such as the “Waste index”
[9] and material flow analysis method
[10], to quantify C&DW materials at the site level, where accuracy relies on data collected from site visits and industry surveys.
In recent years, the emergence of BIM technology has provided the Architecture, Engineering, and Construction (AEC) industry with an Integrated Project Delivery (IPD) approach for information management. Building information can be conveyed and exchanged seamlessly on an integrated platform throughout the project life cycle. This feature allows BIM-based applications such as design coordination, material quantity take-off (MQT), 4D phase planning, and cost estimation to be applied in the C&DW domain
[11]. More specifically, BIM can facilitate decision-making for C&DWM planning by systematically predicting waste output, waste generation sequences, and disposal costs.