3.3.5. Investment Barriers
These challenges are related to cost, financing, incentives, and investment, as discussed below.
Lack of financial resources: The primary rationale mentioned by construction companies for rejecting new implementations or improvements is a lack of financial resources and support. Researchers have highlighted that the primary obstacle to adopt digital technology in the building sector is the shortage of green finance and regulations at the corporate and governmental levels [
4]. There is no denying that price is the primary factor when purchasing building materials. So, the high cost of retrieving and preserving the materials’ residual value at the end of their useful lives makes virgin materials desirable for new projects [
4].
Lack of financial incentives: The adoption of digital technology can be greatly impacted by a lack of financial incentives. Efficient reuse of construction materials and a CE will require large-scale data management. Data from existing structures and materials can be labour- and cost-intensive to gather, digitise, and manage [
27]. Furthermore, the authors underlined that the absence of financial incentives is a significant obstacle to enabling efficient data management. It is challenging to develop a business plan for the large-scale reuse of construction materials without financial incentives from the government or the industry [
27]. The absence of government financial incentives affects not only reuse but also the proper implementation of BIM [
25].
High implementation costs: Using cutting-edge technology for CE in the construction sector can be costly and necessitate large infrastructural, software, and hardware investments. Aside from the cost of hardware and software, a significant financial cost is associated with the workforce’s lack of knowledge and proficiency with digital technology [
28]. The authors have drawn attention to the considerable implementation costs related to the use of BIM [
25], blockchain, IoT, artificial intelligence (AI), big data analytics (BDA), material passports, and extended reality [
3,
9,
22,
28]. Moreover, these knowledge-intensive enabling technologies are associated with high R&D intensity, rapid innovation cycles, and high-skilled employment, resulting in substantial capital expenditures [
14]. Moreover, DTs are becoming a niche area that necessitates convincing many organisational stakeholders to make investment decisions [
26]. The construction industry is burdened by the upfront expenditures associated with its adoption [
9,
26]. However, the construction industry must carefully weigh the implementation’s costs and expected advantages to ensure the investment is worthwhile. In the opinion of [
14], choosing the genuinely effective technologies in an assessment of their whole life cycle necessitates the use of life cycle assessment procedures that emphasise the advantages (e.g., material savings) along with the drawbacks (e.g., the high energy consumption of DTs) of employing advanced technologies. However, financially fragile construction organisations may find it difficult to adopt new DTs because of the significant capital investment involved [
13].
3.3.6. Barriers Associated with the Nature of the Construction Industry
These barriers examine the traits of the construction sector, including the slow uptake of new technologies, fragmented stakeholder involvement, lack of labour training, and CE-based knowledge management.
Slow uptake of new technologies in the construction industry: The construction sector is well known for its slow acceptance of new technologies [
15,
23,
26] and has been the least digitalised in recent decades [
7]. Industry appears to oppose technological advancement rather than waiting for an appropriate application of DTs. Also, how existing construction organisations function towards CE implementation reveals a lack of progress in digitalisation [
4]. Thus, the construction industry may radically change if organisations successfully transition to digital circularity and encourage digitisation across all organisational levels [
4,
15]. Similarly, as discussed by [
6], the construction industry lacks clearly defined indicators for integrating digital technology and CE. Furthermore, they noted that circularity technologies are still in their infancy within the industry. However, some authors argue that although DTs have enormous potential, there are insufficiently validated technologies and tools for construction-related CE [
10]. The scalability challenges related to the application of blockchain technology for CE in the construction sector were also revealed by [
22]. Although several cutting-edge technologies have demonstrated potential for promoting circularity, their scalability and applicability for larger projects or wider adoption may also be limited [
9]. Thus, a thorough approach regarding both technical and economic factors must be considered to design scalable solutions to apply CE in the construction industry [
9].
Involvement of fragmented parties: Researchers argued that the enormous number and dispersed nature of stakeholders involved in the construction industry are obstacles to improving construction industry practices [
18,
19,
23,
26]. The industry’s split structure creates fragmentation among stakeholders at various project stages, increasing the likelihood of errors and poor interaction among these stakeholders, directly hindering the adoption of DT-enabled CE within the industry.
Lack of trained workforce: The adoption of DTs enabled CE implementation in the construction industry, which is severely hampered by the lack of skilled people on-site [
6,
14,
28]. Furthermore, stakeholders involved in enabling technologies for CE implementation need to be highly knowledgeable and qualified [
14]. The existing challenge for the organisations is to find highly skilled and knowledgeable stakeholders to collaborate on DTs-enabled CE projects.
Lack of CE-based knowledge management: In their study, ref. [
6] found that the industry lacks efficient knowledge management systems, making deploying DT-enabled CE in the construction industry difficult. It is clear that an organisation suffers greatly when CE-based knowledge is lacking, and significant time is lost looking for pertinent information rather than finishing tasks with an established goal.
3.3.7. Technological Barriers
These barriers are caused by technological constraints that restrict the appropriate application of digital technology to implement CE in the construction industry.
Disposal of devices (technology disposal): Disposal of technology raises issues as it may have a negative effect on sustainability goals and the environment, either directly or indirectly. There are concerns regarding the disposal of technology, which will directly or indirectly impact the environment and cause negative achievements in sustainability. IoT devices’ effects during their disposal raise concerns, even though their deployment helps to enable circularity in construction [
3]. Furthermore, the authors also emphasised the issues with sustainability caused by the manufacture and disposal of extended reality technology.
Elevated power consumption: The utilisation of digital technology to promote circularity raises questions because of the high-power consumption it requires to operate. Blockchain usage necessitates a sizeable computational power [
3]. Thus, the high electricity consumption of IoT has been highlighted by authors, as another negative environmental impact.
Sustaining the use of technology: These barriers are associated with MPs, BIM, AI, digital twins, IoT, BDA, and RFID. MPs are intended to monitor material flows throughout the life cycle of buildings and record material documentation that will facilitate the recovery of materials for reuse during the renovation and demolition phases. However, there is a requirement for manual updates each time a building undergoes modification, which remains a significant barrier to the practical implementation of MPs [
26]. Additionally, incomplete information poses a significant obstacle to the effective compilation of an MP [
11]. Initially, BIM enhanced design quality by combining all pertinent data from several disciplines into a single model. In contrast, BIM provides a means of smoothly incorporating circular economy concepts into building projects. Concerns about BIM software’s frequent updates and changes to newer file formats have been raised, possibly rendering BIM models incompatible [
26]. The success of every AI model or project heavily depends on the labelled data, known as training data, which are used to teach machine learning algorithms or models to make the right decisions. The AI models are highly susceptible to biases resulting from the training data [
26].
Furthermore, researchers highlighted that the complexity of the code makes it very challenging to create a rule-based program [
21]. Circularity in the construction is expected to be made feasible by DT, which connects real-world data with digital data. Even though DT and CE are a combination, the capacity of a system to carry out its intended function over an extended period consistently and without failure is referred to as reliability. Reliability is an essential consideration in the context of the IoT, as problems with malfunctioning devices may have serious consequences [
3]. BDA has become vital to producing insightful information for circular construction decision-making. BDA calls for intensive analysis to extract valuable information from vast data [
3]. One of the existing obstacles to utilising RFID is the lack of technological and functional knowledge, which determines where the RFID tag should be installed [
2].
Some researchers have highlighted that RFID tags have a shorter service life (15–20 years) compared to construction components. It is also clear that a significant gap exists since stakeholders have limited time to manage an asset during its useful life. Stakeholders’ interest in RFID is significantly curtailed when an asset is transferred to the user after it has been sold or the warranty has ended. Even though DTs pave the way for circularity in construction, the issues related to those technologies make it challenging to sustain their benefits.
Lack of recognition for DTs: A new paradigm can be adopted more quickly and easily if the technology and information are accessible to advance it [
7]. DTs were not recognised in the circular construction due to the lack of knowledge and understanding related to them [
28]. Furthermore, the absence of a vital ICT infrastructure in the construction sector prevents DTs from being used diligently [
24]. Construction organisations are rushing to embrace DTs to demonstrate their social responsibility without having a firm grasp and awareness on them. The adoption of CE is hampered by the construction industry’s poor technological and eco-innovation ability and immaturity in enabling DTs and solutions [
10,
22]. Despite BIM’s widespread use, some stakeholders remain with limited awareness and knowledge [
25]. In addition, they have emphasised that the lack of maturity of CE in the construction industry led to a shortage of investment in tools and technologies necessary for CE adoption. The underappreciation of DTs reflects the double-barrelled impact of change aversion on CE adoption [
10]. In the modern digital age, recognising the opportunities presented by digital technology has become essential for competitive survival. It is imperative to acknowledge the role of DTs in the construction industry to enable circularity in construction.
Lack of integrated CDW processes, tools, and practices: Although several studies have highlighted the potential for digital technology to support integrated construction and demolition waste management (CDW), there are still insufficient integrated CDW procedures, tools, and practices. The industry still lacks tools for detecting, categorising, and certifying salvaged materials [
5].
Lack of circularity in product design: Lack of material alternatives available in the industry inhibits product design growth [
1]. Furthermore, increased supply chain complexity lessens the circularity of product design. Construction circularity is delayed by ineffective green building design development [
5]. The practical use of design for deconstruction (DfD) is hindered by a lack of standard spatial geometries and limited visualisation in this context [
5]. Ref. [
10] emphasised that insufficient technologies are available to design for a building material’s end of life.
Absence of sufficient technologies for reusable, recycled, and recovered materials: The current state of recycling technology is immature and stems from a lack of technological advancement that is necessary for the appropriate recycling of materials [
8]. Inadequate material separation, administrative obstacles, and a deficiency in making readily disassembled goods hinder recycling procedures [
5]. Complications with material recovery at the end of life are another technological barrier to the implementation of CE [
1]. Insufficient technological capabilities for managers to recover and reuse resources is a significant barrier impeding circularity [
8].
Lack of proper information management system: The absence of an information management system was linked to the lack of transparency and availability of technical data on construction elements, extending the gap to the current modelling tools and material database [
5]. Furthermore, there are still insufficient databases and information on constructing, particularly at the end of life, due to the restricted number of existing CE-oriented databases [
6]. The limited availability of information that aligns with the end of life has impeded the adoption of digital technology for circular buildings. A significant quantity of data and information may be needed for circular solutions about inventory, management, and asset end-of-life [
2]. Still, it is not easy to track recycled materials using trustworthy information systems [
10].
3.3.8. Stakeholder Barriers
Stakeholders are groups of individuals who have the potential to influence the objectives of an organisation, its progress, and even its existence. This set of barriers delves into the stakeholders’ unwillingness to adapt and their inadequate engagement, knowledge, and understanding of using DTs to enable CE.
Resistance to change: The resistance-to-change mindset among the stakeholders who are used to traditional construction processes is one of the most significant barriers to the adoption of new technologies for CE in the construction industry [
3,
4,
9,
14,
24,
26]. Construction stakeholders are typically conservative in the context of early acceptance and diffusion of technological innovation [
24]. Stakeholders’ perceptions are influenced by ease of use and technology acceptance, which discourages them from adopting DTs at this early stage [
4]. A familiar problem stakeholders face is figuring out how DT-enabled CE may help the construction industry by cutting waste and increasing productivity [
9,
14]. BIM, GIS, and RFID are the contemporary ICT-based decision-making tools currently utilised in the construction industry [
24]. However, industry stakeholders have not yet widely used IoT, big data, and blockchain, potentially boosting the practice of CE in the construction sector. Ref. [
3] also highlighted the limited adoption rate of material passports and material databanks among industry stakeholders. As per [
26], respondents acknowledged that even if they obtain BIM models from architects, they still prefer using 2D drawings for their jobs. Since executive support and client demand for adopting BIM are lacking, there is a general resistance to change [
25]. Furthermore, some participants in the [
26] study highlighted that although new technologies have been implemented in their organisation, some colleagues might be hesitant to use them since they have been using the same programs and processes for a long time. In the [
14] study, participants highlighted the possibility of losing their professional identity because of the industrialisation process made possible by specific technologies. Moreover, with the introduction of digital technology, stakeholders believe they will be integrated into the industry as technicians, frequently offering less flexibility and income than the free profession. Stakeholders prefer to adhere to the status quo, as more significant penalties and a lack of high-tech expertise are associated with project delivery failure [
24]. Even though several ICT-based decision support tools have been developed to aid in the implementation of CE, it is not easy to persuade stakeholders that developing innovative CE business models is essential to surviving in the resource-intensive market of the future [
24]. A change in the attitudes and behaviours of the participants is necessary for the transition from linear building to DTs, enabling circular construction.
Lack of skills: The advent of digital technology may have created a skills gap in the industry, which could restrict the use of these resources to advance CE in the construction industry [
9]. Utilising DTs for CE in the construction industry demands stakeholders with specific data handling, programming, and analysing expertise. The research by [
3] noted that stakeholders in the construction industry lack the technical know-how to create and apply AI models. In addition, the authors confirmed that specific equipment and stakeholder skills are required to reap the full benefits of extended reality technology. The authors also emphasised that the lack of BIM knowledge, skills, and experienced workers in the construction sector hinders the wider application of BIM [
25]. Inadequate expertise in digital technology leads to a lack of competency necessary for managing technological implementations like blockchain [
22]. Furthermore, a lack of experience among stakeholders raises concerns about the practical commitments that come with technological progress [
14]. Thus, the industry faces a significant skills gap that appropriate solutions must address.
Lack of awareness among stakeholders clients, and the public: Stakeholder awareness and engagement are the key factors that facilitate a seamless transition from linear construction into a circular one. Lack of understanding among stakeholders and clients is the most significant obstacle impeding the shift to DT-enabled circular construction [
4,
6]. Stakeholders must become conscious of the environmental impacts created by the construction industry and urge circular principles by changing their disposal-focused and cost-driven perspectives. The study conducted by [
7] highlighted that the public ignores the advantages and practices of CE without sufficient knowledge. Hence, inadequate client and public awareness of CE processes and benefits is one reason why constructions still adhere to linear construction processes. A lack of awareness about DTs enabled CE in the construction industry, which can also be interpreted as deliberate ignorance or failure to learn or change. It is imperative to raise awareness of DT-enabled CE and demonstrate its advantages for the economy and environment to encourage stakeholders, clients, and the public to embrace DT-enabled CE practices. Stakeholders, clients, and the public may lose the chance to produce more circular results if they lack the necessary knowledge and comprehension. The public, clients, and stakeholders must change their viewpoint and admit that they are hindering the implementation of CE. Additionally, stakeholders in the construction industry are not even aware of the advantages new technologies can provide [
7,
14].
Lack of commitment from stakeholders: A significant obstacle remains the absence of stakeholder cooperation and communication [
3,
18,
22]. Furthermore, gathering project-related data to support circular construction is challenging as the industry is so dispersed [
3,
16]. The inability of many stakeholders to collect, handle, share, and manage data regarding building materials and recognise information’s worth in embracing circular principles is an additional barrier to data management [
27]. Demanding the construction community’s shared commitment to data integration throughout the value chain is one of the most significant barriers [
20]. Stakeholders’ unwillingness to exchange information amongst themselves and with other parties in the value chain hampers data management and material reuse in the AEC industry [
27]. Moreover, there are still issues with unclear roles and responsibilities, poor communication, and a lack of teamwork in the BIM implementation process [
25]. Due to their unwillingness to cooperate, AEC industry stakeholders cannot support the circular economy. There is a substantial chance of failure when implementing any CE program without significant collaboration from the key stakeholders.
Cultural resistance: The expected values, beliefs, and norms that shape stakeholder behaviour and their work process are called culture. Adopting new technology within organisations is hampered by existing cultural behaviour, which necessitates systemic transformation [
26]. Stakeholders must adopt new attitudes and behaviours that modify the construction industry’s culture to enable the transition from linear to circular construction. However, such a significant change is challenging to implement in the sector where adopting supply chain fragmentation and hesitant technology are typical [
26]. According to [
22], cultural variations in the construction industry also impact the adoption of new technologies like blockchain. Cultural variances and technological advancements influence one another’s growth.
Reluctance to adopt DTs: Employees are unlikely to embrace new technology unless their work environment encourages creativity, cooperation, and a readiness to change. The study by [
26] showed that a full implementation of DTs in daily operations is needed for both digitalisation and CE, which are currently limited to pilot projects and the company’s corporate vision. Ref. [
22] states that organisations typically oppose using DTs in favour of maintaining the status quo. Organisational resistance makes a company rigid and unable to adjust to internal or external demands for change.
3.3.9. Data-Related Barriers
These are the barriers related to the lack of quality, quantity, nature, and management of built environment-related data. The most significant data-related obstacles found in the literature are the lack of built-environment-related data, lack of clarity on the required data, poor data handling and management, poor-quality data, unavailability of web-based databases for secondary products, lack of data interoperability, and absence of data standardisation and data security barriers, which are discussed below.
Lack of built-environment-related data: One of the main concerns regarding adopting the DT-enabled CE is the absence of relevant data from the construction industry. Large volumes of data are required to efficiently operate advanced technologies like deep learning, BDA, and machine learning [
3,
5,
7,
9]. The scarcity of data sets makes it challenging to enable AI models for systemic circularity in the construction industry [
6]. Furthermore, there is still a lack of technology applications focused on CE due to the shortage of comprehensive databases [
7,
24]. It is challenging to gather project life cycle data to support circular construction [
16]. Ref. [
6] pointed out that there is still a shortage of data about the end-of-life stage, emphasising how little focus is placed on it. Furthermore, the authors stated that data and information for prediction in a CE are not easily accessible everywhere in the world for appropriate demolition auditing. However, lack of documentation of the materials used in construction is a typical occurrence in the industry, but this hinders the materials’ reusability in the future [
5,
27]. Additionally, the sector lacks critical information for prediction and disassembly, which is imperative for an effective deconstruction process [
7]. Data about building materials and supplies are frequently absent, incomplete, inaccessible, or not digitalised, which is one of the significant issues of the modern industry [
27]. The absence of defined methods for collecting and storing data in the construction sector leads to a lack of data availability, complicating the adoption of cutting-edge technology [
9]. Moreover, ownership, access, privacy, and trust-related problems within the industry contribute to a shortage of data [
5]. There is still plenty of work to be carried out regarding data collection, processing, and reprocessing to create meaningful information, and ongoing data recording is needed to support decision-making [
16]. Data are crucial to the application of circular practices throughout the whole life cycle of each construction project. A lack of data from the project may miss the opportunity to create more circular and profitable outcomes; Ref. [
7]. If efforts are not made to address the data issue, future research on DT-enabled CE may be misdirected.
Lack of clarity on the required data: Uncertainty about the requirements for circular strategies contributes to a lack of built-environment data [
26,
28]. BIM provides a database for MP generation and facilitates data sharing between project stakeholders to allow CE. However, there are uncertainties regarding data requirements for generating MPs [
26]. Due to the lack of fully defined DT standards, data requirements cannot be appropriately specified [
28]. More efforts must be undertaken to critically assess stakeholders’ data requirements to enable them to make informed decisions on CE [
26]. Stakeholders lack the expertise to evaluate what technologies should be developed and what data they might need to promote circularity in the construction sector. Lack of clarity on the required data barrier must settle down as soon as possible to reap the DT-enabled CE implementation benefits.
Data handling and management: Data handling and management of collected data appear to be a prominent barrier to CE implementation as technologies such as AI, IoT, and BDA require and rely on large quantities of data for their functioning. BDA offers a variety of solutions and forecasts for the future by combining all other technologies, including BIM, AI, and IoT [
3]. Enabling circularity requires the management of varied data over the whole life cycle. Data are produced at each construction phase from various sources, such as sensors, monitoring equipment, and BIM [
3]. While the integration of life cycle assessment (LCA) and BIM offers significant opportunities, managing complex data is undoubtedly challenging [
17]. Moreover, it leads to challenges in data handling related to accessibility and assessment, which necessitates a substantial time and financial commitment [
20,
21,
22]. DTs and solutions facilitate the open, transparent, and standardised sharing and connecting of data across the various stakeholders in the supply chain. So, a proper data management mechanism is a critical problem for DT adoption, especially for MPs [
26]. Also, coordinating data management for material reuse without clear standards is challenging in the construction industry [
27]. The implementation of blockchain is still beset by challenges with data gathering and transparency [
12].
Poor-quality data: Data of inadequate quality cannot meet the purposes for which it is being used. Low-quality data can erode trust in shared information due to insufficient coverage, disparate data formats, random collection practices, and monitoring [
5]. Additionally, the writers stressed that issues with ownership, access, privacy, and trust in the sector could potentially hinder the acquisition of high-quality data [
3]. They highlighted the need for vast quantities of high-quality data for DTs to operate as intended. The vast quantity of data gathered for DT operations cannot be guaranteed to be of high quality [
13]. The quality of the data input influences the BIM outcome [
3]. The authors also highlighted how poor construction data quality impedes using BDA. Poor-quality data lead to inefficient decision-making and reduced opportunities for maximising CE.
Unavailability of web-based databases for secondary products: According to circular principles, secondary products must have an extended life until they reach a point at which they can no longer be utilised. There is a lack of documentation in the management of used building materials, which raises concerns about their ultimate circularity [
5]. Furthermore, inadequate material property information for materials listed on a web marketplace typically discourages stakeholders from purchasing them. The exchange of usable secondary materials and products is hampered by the lack of an efficient CE web-based waste exchange system [
6]. Moreover, reusing secondary materials through marketplaces raises the issue of meeting quality requirements, as measuring the physical quality of secondary products is tedious and requires expert inquiry [
6]. As a result, the lack of a web-based database for secondary products deters potential users from considering them for further purposes.
Lack of data interoperability: The transmission of information between stakeholders along the value chain is hampered by data being frequently kept in disparate repositories, in disparate forms, with differing degrees of ownership and accessibility [
27]. Data transparency is believed to be necessary to facilitate interoperability [
27]. Integrating advanced CE technologies with current systems or technologies might be challenging. It is not easy to configure these technologies to ensure process and data interoperability for diverse stakeholders within the industry [
9,
24].
Additionally, the authors noted that BIM model versions vary since the software is frequently updated and that future compatibility issues may arise with newer file formats [
25,
26]. As per [
22], their incompatibility could significantly hinder amalgamating concepts such as CE, blockchain, and construction waste management. Furthermore, they added that there is a need for a proper system conversion to reap the benefits of blockchain-enabled CE [
22]. It is difficult to ensure technological interoperability between LCA and BIM technologies [
17]. Interoperability and data sharing are difficult to achieve while using various DTs based on disparate languages and standards [
26]. Moreover, the authors emphasise the importance of incorporating digital technology into existing systems. A multifaceted strategy involving technical solutions, teamwork, and a long-term outlook is needed to address the issue of lack of interoperability [
9]. Ineffective data management can be caused by a lack of technical interoperability, which can slow down the construction industry’s practices of reusing materials [
27].
Absence of data standardisation: Inconsistencies and inefficiencies in the construction value chain may result from the lack of standardisation for adopting these technologies, which may ultimately impede their adoption [
9,
14]. The absence of standardisation presents a significant obstacle to the construction industry’s adoption of cutting-edge technologies for CE. Furthermore, researchers noted that the lack of a national standard for data exchange is becoming an issue for stakeholders [
26]. Consequently, international data standardisation may resolve these issues with data sharing and administration. This requirement for standardisation and open interfaces is a significant barrier to the construction community’s commitment to data availability [
20]. The construction industry must collaborate with industry organisations to develop and implement standardised protocols covering various aspects of advanced technology adoption [
9].
Data security barriers: Digitisation presents a complicated cyberspace network, making industries vulnerable to cyberattacks despite its apparent benefits. The fragmented nature of the construction sector, where different stakeholders have varying requirements for data privacy and security, has always presented significant hurdles in this regard [
9]. The construction industry has witnessed a surge in cyber risks, making the infrastructure for cyber security imperative for all organisations [
4]. Nowadays, blockchain is frequently utilised in the construction sector for CE-related solutions, which creates privacy or security concerns and legal liabilities [
3,
22]. Furthermore, ref. [
3] stated that data security is required as complete building data are included in material passports and data banks.
Additionally, DTs are highly susceptible to privacy issues caused by cyberattacks [
3]. Since these technologies include collecting, storing, and exchanging sensitive data, implementing them to promote CE in the construction sector may present significant difficulties [
9]. Formulating data privacy and security guidelines and measures to safeguard sensitive data are critical areas for future growth in this discipline [
9].