The transition towards a Circular Economy (CE) has been receiving an increasing amount of attention in the built asset industry. One of the key aspects of CE is traceability, which can enable the identification and tracking of materials, products, and their associated value throughout their entire lifecycle. However, achieving traceability has been challenging in the built asset industry due to the complex nature of construction projects and a lack of awareness about the benefits of traceability in achieving the circularity of building products and materials. A limited number of frameworks or guidelines exist to support traceability in the built asset industry. In many cases, several of the existing traceability standards, strategies, and guidelines must be identified and framed to support development and implementation of theories and models applicable within the built asset domain.
1. Introduction
The built asset industry is a significant contributor to global waste and resource depletion. According to the World Green Building Council, the construction and demolition of buildings account for 40% of global energy consumption and 30% of global greenhouse gas emissions and are responsible for 25% of waste
[1]. Transitioning to a Circular Economy (CE) presents a viable alternative that seeks to keep materials and products in use for as long as possible, thus reducing waste and promoting sustainable resource use
[2]. One of the main goals of CE is to create a closed-loop system in which materials and products are used and reused as efficiently as possible, without creating waste or depleting resources
[3]. This approach is often contrasted with the traditional linear model of production and consumption in which resources are extracted, transformed into products, and then disposed of, often in a way that is harmful to the environment
[4][5]. As the principles of CE are becoming more prevalent in various fields of research, there are still several barriers associated with achieving circularity of built assets, including the complex supply chains involved in the distribution of products
[6], the difficulty of tracking materials and products through the various stages of their lifecycle
[7], and the lack of incentives or effective collaboration among industrial practitioners to promote circularity
[8][9].
One critical aspect of CE is traceability, which enables the identification and tracking of materials, products, and their associated value throughout their entire lifecycle. The notation of traceability can be defined as the ability to track and trace the history, location, application, and movement of materials, products, or systems from the point of origin to the point of consumption or disposal
[10][11], while providing detailed information about the transformation processes, intermediaries, and actors involved in each stage of the value chain
[12]. Such abilities can provide opportunities to address current CE challenges by enabling full transparency of transformed and shared information throughout lifecycle stages, as well as supporting potential End-of-Life (EoL) options such as ability to reuse or recycle the disassembled products and materials
[13]. To date, the concept of traceability and its applications are widely investigated in various domains including food industry, software engineering, manufacturing, and aerospace. In such domains, several published frameworks and models can be found describing the key characteristics and components of traceability to meet CE goals and outcomes
[11][14][15].
In comparison to other domains, the literature on traceability studies is relatively limited in the built asset industry
[16]. There is a poor understanding about the role of traceability in enabling circularity of building products and materials across various lifecycle stages
[17]. Most of the existing studies have focused on specific aspects of traceability, such as the use of advanced information technologies (e.g., blockchain technology) to accelerate traceability processes
[18], or have been limited to case studies of individual projects or companies. There is an apparent lack of integrated approaches to frame current industrial standards, guidelines, and strategies linking their relationships in real construction projects
[13]. The main reasons for slow adoptions of traceability in the built asset industry can be investigated due to the fragmented nature of construction projects, very long asset lifecycles, and a high volume of stakeholders involved
[17]. To address such issues, many academic publications put emphasis on the necessity to develop and implement integrated traceability frameworks to enable the circularity of products, materials, and systems in the built asset industry
[13][17][19].
2. Traceability Framework in Built Environment
2.1. Circular Economy in the Built Environment
Waste generated from construction, renovation, and demolition (CDR) in Canada generated more than 4 million tons in 2021
[20]. To divert this significant amount of waste from landfills, the Canadian government is pushing the built asset industry towards a CE model by replacing the EoL concept with reducing, reusing, and recovering materials across construction and operational lifecycle stages
[20]. While the body of literature pertaining to a circular future is rapidly growing, many scholars and industry experts have highlighted the significant challenges in transitioning to this new economic model
[5][21][22][23]. There are several strategic and political challenges hindering this transition such as resistance from stakeholders in the industry who are accustomed to traditional linear approaches and do not see the value of the CE models
[8][24] or the competitive nature of markets, which may make it difficult for organizations with narrow profit margins to justify the additional investment and effort required for circularity
[25]. From a technical perspective, challenges include effective lifecycle information management to increase the circularity of materials and products within and between organizations and regulatory bodies in the built asset industry
[26]. Achieving circularity depends heavily on the availability of data that is relevant, reliable, and readily accessible
[27]. Without such data it is hard to track the properties of materials, products, and systems and measure their economic, social, and environmental impacts
[28].
One opportunity for accessing required data is the use of materials passports (MPs)
[29]. MPs are a set of digital documents containing composition data, environmental product declarations (EPDs), and provenance of building materials and products and showing their potentials for recovery and reuse
[30][31]. A growing number of passport-types have been proposed by scholars and practitioners
[32][33][34]. However, it may cause difficulties in collecting and matching incoherent data from multiple MPs
[35]. Examples of MPs include the following:
-
Buildings As Material Banks (BAMB): this MP describes data and their implementation strategies in the built environment. All necessary information about materials and products pertaining to CE is hierarchically categorized into several levels (
Figure 1) such as material properties, certifications, logistics, etc. The project has also established a digital platform which connects individual components of the buildings by displaying their uses and values in the marketplace
[30].
Figure 1. Categorization of MP data (adapted from BAMB
[30]).
-
3XN Architects: this MP provides guidelines to collect CE data across a building’s lifecycle stages. The collected data need to be linked to a database enabling traceability of all building components and parts with their technical and functional specifications
[36].
-
Madaster: this project frames MP data based on the building’s layers (e.g., structure, skin, services, etc.). The MP also provides circularity indicators to calculate the amount of virgin, recycled, reused, and renewable materials that are incorporated within a building. Madaster’s cloud platform can connect to Building Information Modeling (BIM)-based models and allows users to create and develop a unique passport for buildings or objects
[37].
In addition to the application of MPs, transition to an advanced CE requires a high degree of digitalization and automation
[38]. The main barriers that hinder this potential are primarily related to what can be described as an information gap between industrial parties
[39]. This information gap appears when there is no transparent and common understanding about what, when, which, where, why, and how CE data are circulated and exchanged among the involved parties in a project. It is becoming increasingly important to close this gap by ensuring traceability of all relevant CE-related data and linking them into a structured knowledge base
[40][41]. Nevertheless, disregarding digitization’s upheaval influence, there are still certain issues which need to be addressed. These might include a digital gap across lifecycle phases and project stakeholders
[42]. Finally, traditional project delivery practices tend to create barriers between project stakeholders which leads to a collaboration gap
[43].
Figure 2 demonstrates these gaps across asset lifecycle phases. To fill these gaps, an integrated and automated solution is very much needed to link and put key components of circularity into relationship.
Figure 2. Overview of current gaps in asset lifecycle phases.
2.2. Concept of Traceability across Domains
Traceability of materials and products is recognized as one of the major concerns in an increasing number of CE studies and practices across various domains [44]. Although there is no definitional ambiguity that encompasses all aspects of traceability [17], the notion of “traceability” has been defined in the literature as listed in Table 1.
Table 1. Definitions of traceability.
Ref |
Definition |
Context |
Year |
[45] |
“The ability to trace the history, application, or location of an entity by means of recorded identifications”. |
ISO8402 |
1994 |
[40] |
“The ability to access any or all information relating to that which is under consideration, throughout its e tire lifecycle, by means of recorded identifications”. |
Food industry |
2018 |
[46] |
“Client requirements have to be presented in a manner that will facilitate: (…) [t]he traceability of design decisions to original requirements throughout the life cycle of the facility”. |
AEC 1 |
2000 |
[47] |
“Traceability involves knowing where the product or raw material comes from, real-time location throughout the supply chain, and its conditions regarding pre-set quality at each stage of the roadmap”. |
AEC |
2021 |
[13] |
“The ability to follow information related to a product through its supply chain” (p. 3) providing a number of uses: quality and safety, minimizing scandals that damage company reputations, improved supply chains, and enhancing trust”. |
AEC |
2017 |