4.2.1. Theme 1: Regulatory Enablers
The transition to the circular economy in the construction mega-projects is related to the existence of clear laws and regulations. The interviews underscore the importance of having proper regulation, materials certifications, incentives, government and private initiatives, and existing successful examples of CE adoptions in the sector. The subthemes below discuss the regulatory enablers that facilitate the transition to circularity practices in the construction of mega-projects.
Law and legislation are a major agent for the transition to the CE in the construction of mega-projects. Most participants emphasised the difficulty of adopting CE due to the lack of mandatory obligations for the main parties in the projects through legislation. Legislation should, therefore, be referred to in contracts with clear roles and responsibilities of each party. In this regard, a project manager of Project B stated the following:
“Also regulations, … very important the clear regulations. It’s very important for everybody in the projects, so they will understand their role, they will understand what to do …”. (C1-PM2)
This view was supported by the contractor of Project A who confirmed that clear legislation will help the contractor adopt CE principles in the project and will protect him, as it is stated in the clauses of the contract. Their statement reads as follows:
“… we need legislation to support the contractor to do that … because the contractor he cannot request anything from client to accept this kind of reusing or recycling material because he do not have a specific clue or a specific statement in .. his contract enhancing this. So he don’t want to go to the headache by requesting that ....”. (CT1-PD2)
The participants see legislation as an enabler to solve other obstacles to CE transition, such as culture and awareness. They think that the existence of CE is supportive to the spread of CE as a new method and raise awareness about it. This is confirmed by the project director of Project A, who says the following:
“I think you’ll have to start with regulation. When I talk about the awareness or a culture of people, it can be changed by regulation only. So since we have regulations that stop us from doing some wrong practices that will push everybody to use reused material or recycled …”. (CS1-PD1)
The number of times that laws and regulations were mentioned by the professionals of the three projects and the different stakeholder representatives (client, consultant, contractor) underscores the significance of the need for a robust regulatory framework to mandate the incorporation of CE in the construction of mega-projects. This finding is repeatedly presented in both developed and developing countries, as the regulation is a backbone for the circularity adoption. For instance, in the UK and Australia, Adam et al. [
25] and Shooshtarian et al. [
33] emphasise the importance of regulations being in place to help raise awareness of CE within the sector. Similarly, in developing countries such as India [
36] and Oman [
37], researchers confirm the need for mandatory obligation from project parties through robust regulations and policies. Conversely, in the Saudi Arabian building sector, Aljaber et al. [
17] rank CE policy as fifth, which indicates less priority for some regulatory frameworks compared to this study.
- 2.
Governmental and private Initiative
Governmental and private initiatives are critical for the transition to CE in the building sector. Six participants emphasised the need for initiatives with clear indicators and potential prizes for organisations to encourage CE practices in their projects. They cite the local content initiative as an example, which imposes a specific percentage of domestic materials in government contracts with the private sector. For instance, the client project manager at Project C states the following:
“Also, I can say we have good example of local content initiative. So having circular economy initiatives similar to a local content idea, this will help to achieve the needed circular economy practices. ….”. (C3-PM2)
Therefore, the existence of successful initiatives in the country will encourage organisations in the sector to integrate CE practices into their projects. This is asserted by two studies in developed countries, USA [
34] and Australia [
33], as they argued that government or private initiatives are a driving factor towards circularity.
- 3.
Case Study (Show Example)
According to our findings, one of the primary enablers for CE implementation is the availability of case studies/previous examples that incorporate the circularity principles in its practice, particularly with regard to cost-saving and best practices across the board. Furthermore, quantifying the benefits and existence of empirical evidence can promote the adoption of CE in the building sector. For instance, the client project manager at Project B stated the following:
“I can also add a very important enabler in my opinion, let say clients or investors …, if they start with one project .. do it based on circular economy concept like for example using recycled materials in the project. Then they said this is the benefit, this is the saving that we have and this is how we build it based on these sequences and this procedure. This … will help everybody to follow even the private sector they might follow us to do the same ...”. (C2-PM2)
The participants highlight the significance of showcasing the tangible benefits of CE adoption. Additionally, it shows the importance of practical procedures and benchmarks in the sector which can help promote CE. As such, this can provide robust evidence of the potential benefits associated with this principle. This is supported by studies in developed countries by Adam et al. [
25] in the UK and Shooshtarian et al. [
33] in Australia, who emphasise the need for tangible evidence to prove the socioeconomic and environmental advantages of a transition to circularity. Whereas, in developing countries, it is either mentioned as less important or overlooked.
- 4.
Incentives
Incentives for CE transition are critical; the primary incentives relate to fiscal support, such as an exemption from tax for the procurement of local materials, which not only enhances CE but also supports the economy of the country. Furthermore, prioritising loans for monetary support and simplifying the process of hiring foreign experts were considered effective measures to support the transition towards a more circular construction sector. For instance, a designer of Project A mentioned the following:
“Also, the incentives, first incentive should be for the developer who is doing the right thing. .. give them some kind of tax free to source material locally. Give them priority to get bank loan, give them priority to get the knowledgeable people to come in the country easily to work for them”. (C1-D1)
The incentives can change the culture in the sector and raise awareness. Furthermore, rewards offered by the public authority can motivate organisations to align their practices with CE principles and motivate other organisations to shift towards more circular practices. Studies by Guerra et al. [
26] and Shooshtarian et al. [
33] assert that CE in the construction sector needs incentives from governments to encourage the main parties to transition towards circularity.
- 5.
Certification
Despite the benefits of using reclaimed materials in construction, four participants expressed the need for quality assurance to ensure the best materials selection. The participants expressed the need for the materials verification process and called for governmental oversight and the establishment of standards and certification systems, such as what the Saudi Standards Metrology and Quality Organisation (SASO) did for other materials. The certification theme is thus emerging as a critical factor for enabling the shift to reclaimed materials. The existence of standards and certifications provided by governmental authorities enhances the reliability of reclaimed materials and items. For instance, the contractor of Project A stated the following:
“… they have to make ... some specifications for that and make some like certification. For example, SASO the standards for material ... in the kingdom. They have to give some testing certificates of the material, … material take certificates from SASO, that means very good material in a very good condition” (CT1-PD2)
This statement highlights the significance of having specific standards and certifications in place for reclaimed materials. The project director underscores the importance of the Saudi Standard, Metrology, and Quality Organisation’s (SASO) role in providing the required tests and certificates for such materials. This viewpoint is supported by a study by AlJaber et al. [
17], which ranked materials certifications among the top five enablers in Saudi Arabian building projects. This indicated that certification provision by local authorities is essential to mitigate the risks associated with the use of reclaimed materials, as it can enhance their utility and acceptance in the market by verifying their quality.
4.2.2. Theme 2: Knowledge Enablers
The awareness of CE and the associated benefits of its adoption are highlighted across multiple participants. It is considered key to the integration of circularity in the sector, as it educates professionals, stakeholders, and the public about the implementation of CE in the construction of mega-projects. The sustainability engineer of the consultant at Project C said the following on this point:
“Firstly, is the awareness of stakeholders in the sector. I see awareness is very important because it needs many efforts to raise it among workers and increase the commitment from client and contractors….” (CS3-SPE1)
By elucidating the circularity principles and their advantages for professionals in the sector and the public, a well-known community will help accelerate the adoption of CE and ensure broader acceptance of the CE system. This is confirmed by studies from both developed and developing countries [
26,
33,
36,
37].
- 2.
Education and Training
Education and training are also key factors for fostering circularity in mega-projects, as they help raise awareness and gain the support of the main stakeholders. Educating and training professionals in the construction field is essential, as they facilitate the practical adoption of CE and enhance the common understanding of the term among the sector parties. For instance, a C3-PM2 stated the following:
“In my opinion, if we want to implement circular economy, we have to start with the … education. The concept itself does not exist in a common way. Especially, … in construction, it’s rarely discussed or rarely known”. (C3-PM2)
This can show the insufficient awareness of CE principles, highlighting the significance of appropriate training and educational programmes.
Furthermore, the participants affirmed the importance of the early-stage incorporation of circularity and sustainability in engineering school curricula for students and junior engineers. The CS1-PD1 mentioned the following:
“Well, this started by teaching the engineers or engineering students … that raise awareness of the engineering students by teaching them about circularity and sustainability principles during design and during construction that will bring to us educated students who can enhance later the sector and improve the sustainability and circularity practices in the construction. So, the new engineers should be aware of these things.” (CS1-PD1)
This has been confirmed by studies in developed and developing countries [
26,
33,
35,
36,
37], which emphasise the need for education and training programmes, considering them as essential driving tools in promoting circularity and equipping professionals and the public with the needed knowledge and skills to understand and adopt CE in the construction of mega-projects.
4.2.3. Theme 3: Technology Enablers
Technological advancements are essential for effective resource management, reuse of materials, and recycling, which are considered to be essential for the CE transition. The feasibility of dismantling or recycling construction elements and materials is heavily dependent on the adequacy of the existing technology in the factories. Furthermore, the advancement of technology in terms of the sorting, cleaning, and recycling of materials highly contributes to the efficiency of the reclaiming processes. For instance, a designer at Project A stated the following:
“… you don’t have resources to do that. Resources in terms of technology. You know, when you .. remove or when you recycle this material, there is a way to dismantle things and you need to have the right technology and the right knowledge to do it in a normal way….”. (C1-D1)
Thus, technological advancement is a pivotal enabler for CE adoption in the construction sector, as asserted in studies conducted in developing [
17,
36] and developed countries [
33,
35].
- 2.
Data
A client in Project C mentioned that the transition to CE will be easier if reliable data are available, affirming the absence of shared data on waste quantity or dismantled elements. The project manager 2 of Project C stated the following:
“… that there is no data and no organisations that specifically giving us the information of the amount of waste materials to be reused…”. (C3-PM2)
Therefore, enhancing waste data transparency and accessibility by collecting data and analysing it for stakeholders can establish a data-driven sector and ease the decision-making related to the recycling and reuse of materials; this is also highlighted by the study by Guerra et al. [
26] in the USA.
4.2.4. Theme 4: Market and Economic Enablers
A key enabler for the CE transition is the existence of effective engagement with competent suppliers in the market. Seven participants indicate an initial challenge in establishing the proper network with suppliers with knowledge of sustainability in the market. Furthermore, ensuring a reliable supply chain for reclaimed materials and having a more mature market to sell and buy reclaimed materials are crucial in the CE transition. In this regard, the director of the contractor at Project A stated the following:
“We have now the local content initiative for example, this localisation program starting from seven years ago, and it’s gonna gradually use local materials in KSA market. … we need to have market, good one, and this can be gradually built by government or other party”. (CT1-PD1)
Thus, the presence of credible suppliers who can deliver the needed materials with reasonable cost and quality, as well as an initiative to have a mature market can facilitate the incorporation of CE practices into the construction sector. This matches the findings of Giorgi et al. [
34] in the EU, Al Hosni and Amoudi [
37] in Oman, and Mhatre et al. [
36] in India, which emphasise the need for market-salvaged materials and logistics to adopt circularity.
- 2.
Cost
The cost of reclaimed materials can be a pivotal enabler as it contributes to cost reduction and provides incentives to project stakeholders to implement CE. A participant in this research emphasises the mutual benefits derived from this heading which are shared between the main parties in the project:
“… I can say something that it have to be mutual benefits between different parties. Because contractor need …, like a benefits from doing that. For example, if they state something like this, we need to build this project but if you reuse like 10% recycled or reused material, we will give you these benefits okay. .., and the cost in total will be less but the contractor is still getting some benefits and similar margin. So, the contractor getting benefits and the client getting benefits of reducing the total project cost”. (CT1-PD2)
Likewise, the transition towards CE in the sector will benefit the national economy, as the country is an importer of construction materials. Decision makers are encouraged to support this strategy, as it helps reduce exports. The CT1-PD2 stated the following:
“… it will improve many things in terms of the construction itself and also for the country itself. You know, we are importing many things. So, if we do that, it will help us to improve the construction and save a lot of money”. (CT1-PD2)
Cost-effectiveness is pivotal to enabling the implementation of CE in the sector. Adopting circularity can offer economic benefits at both the project and national level and facilitate its practical integration. This aligns with the findings in the review of CE drivers by Wuni [
32].