Blockchain is a distributed database system that keeps an ever-growing list of data entries that are verified by the network nodes that are a part of it. Every transaction is detailed in the data, which are kept in a public ledger. Blockchain is a decentralized system that eliminates the need for a middleman entity. Every node in the Blockchain has access to, and shares, the details of every performed transaction. Compared to centralized transactions involving a third party, the system is more transparent as a result of this feature.

2. Supply Chain Management and Blockchain

A supply chain (SC) is a network of parties transporting commodities, services, payments, and information from a supplier to a client. The supply chain for construction projects is dispersed and intricate around the globe ^[1][99]. For instance, student housing at the University of Hong Kong required the delivery of prefabricated modules over 2414.016 km from Jiangsu and, at its busiest, over 200 personnel on the supply chain. This project included more than 20 suppliers from around China ^[2][3][100,101]. A larger lack of trust results from inefficient transactions, fraud, theft, and underperforming supply chains, necessitating improved information exchange and verifiability ^[4][102]. SCM is dedicated to ameliorating employee efficiency throughout the SC. The construction sector supply chain trends deteriorate, which raises the number of transactions, while lowering the average value. The issue of low SCM confidence in the construction industry has long been worsened by disintegrated collaboration ^[5][17]. Blockchain can assist SCM in achieving its key objectives of affordability, reliability, speed, sustainability, and flexibility ^[6][103]. Hence, a digital “token” is created and attached when a physical thing is generated using blockchain technology. The item’s eventual receiver may then authenticate the token, which can trace the object’s history back to its initial place. As no one company or collection of entities can unilaterally modify the information stored inside the Blockchain, the end users have increased trust in the information they receive ^[7][104]. In other words, another way in which blockchain networks can help reduce transactional disputes is by facilitating the transfer of digitalized stakes and providing the authentication of the document validity ^[8][105]. Based on the data from the WOS, 47 academic documents out of 482 were concerned with BCT in the Supply Chain.

3. Smart Contracts and Blockchain

Progression payments are provided in construction projects depending on the value of work conducted within a specified period or after reaching an agreed milestone. Payment terms are outlined in the agreements. Deadlines are often established for generating an invoice, reviewing it, and signing off on it before the payment is due ^[9][106]. The delivery of materials is interrupted due to payment delays, which lowers labor productivity in the construction sector. As a result, the success of building projects and the sector’s viability are impacted. Studies conducted in the UK and other nations since the 1960s have shown that, as a result, payment problems in the construction industry are common and have been a cause of worry for decades ^[10][107]. Moreover, late payments impact the time, cost, and quality; timely payments are necessary for high-quality construction to proceed without interruption. A lack of consistent and prompt payment may cause projects to be delayed, profits to decline, and in the worst-case scenario, the firm may be liquidated. It will also impact the whole supply chain in the construction industry as, for instance, the contractor will not be able to make timely payments to his banks, suppliers, employers, and employees, which would threaten everyone ^[11][108]. Szabo initially suggested the phrase “smart contract” in 1994, describing it as “a computerized transaction protocol that performs the provisions of a contract” ^[12][109]. This agreement should meet the standard contract requirements, including payment plans, liens, confidentially, and even enforcement. Such a contract for smart technology must reduce the need for reliable intermediaries, such as banks, limit purposeful and unintentional exceptions, and achieve economic objectives, including reducing fraud risk, arbitration and enforcement costs, and other transaction costs ^[13][110]. The use of a distributed ledger may be expanded to include smart contracts. In the blockchain environment, the smart contract runs as a distributed application. The program’s trustworthiness is guaranteed because it cannot be altered, and its immutability has been cryptographically validated. The primary benefits of smart contracts include autonomous operation (i.e., no need for a trusted third party) and decentralized service provision ^[14][111]. Consequently, Blockchain enables the representation of individuals as users and the expression of transactions in various forms, including documentation, materials, and cash flow. As it is the most significant of these transactions, the financial transaction stands out as a viable area for cryptocurrency study ^[15][112].

4. Blockchain for Sustainability

Sustainable construction practices have always been at the center of the AEC industry as sustainability is one of the most pressing topics on the international agenda ^[16][113]. Evidence from the past suggests that the building sector is responsible for around one-third of the global rise in carbon emissions and energy consumption ^[17][114]. Additionally, to suit specific demands, sustainable supply chains are dedicated to offering their shareholders quality goods and rewarding services in an economical and environmentally friendly way ^[18][115]. The primary technique for evaluating the environmental effects of a built asset or one of its elements is the life cycle assessment (LCA) model. However, it is not easy to do an LCA study of a built asset due to the abundance of data, synergies, and tradeoffs across the product life cycle phases ^[19][116]. Consequently, not only can blockchain technology provide a traceable and transparent track for products and materials, but it can also give vital information that may be utilized in decision-making as a foundation plan for the decommissioning of a structure and the reuse of the materials in every construction project through the appropriate understanding of their properties and composition. In other words, in developed countries, smarter and more sustainable methods may be implemented due to technological innovation and improvements in the building sector. Blockchain technology has the potential to improve several areas, including supply chain efficiency, financial flows, and the simplicity with which goods may be tracked in real time ^[20][117].

5. BIM and Blockchain

Computer-Aided Design (CAD) tools have allowed architects to utilize digital drawing techniques, rather than paper and pen, to create vertical and horizontal lines. These were the first design-aid tools to help architects perform building design ^[21][118]. From the early restriction of replicating pen and paper to the subsequent supply of many computing and connecting capabilities, the CAD tool approaches have been improved over the last few decades ^[22][23][119,120]. Furthermore, early in the design process, uncertainty and a lack of knowledge often cause the designers to make biased decisions. Multiple stakeholders are involved in the preliminary design in the highly project-oriented construction sector, and poor communication leads to disputes and decreased productivity ^[24][25][121,122]. In recent years, however, the popularity of the BIM process is progressing at a galloping rate in the construction industry thanks to its privileges, such as 3D visualization at the design phase, clash detection, scheduling, cost management, etc. ^[26][27][123,124]. During the building’s O and M phase, BIM can serve as a multipurpose tool to help management organizations accomplish these goals. The BuildingSMART Alliance has defined BIM and its contributions in three ways: BIM is a business process that enables all parties involved in a building’s design, construction, and operation to create and use the data concerning the asset’s condition and performance across time ^[28][29][125,126]. In a sequence of “smart objects,” a BIM contains all building-related information, including its functional and physical properties and the project’s life cycle data ^[30][127]. However, cybersecurity, interoperability, and data ownership are still problems for collaborative BIM. Furthermore, serious repercussions, including financial and confidence loss and reputation, may come from the improper sharing, leakage, or loss of sensitive project information through collaborative BIM platforms, including intellectual property, financial data, and clients’ data ^[31][128]; consequently, Blockchain is well suited to satisfy the security needs of collaborative BIM platforms because of its combination of peer-to-peer networking, asymmetric encryption, encrypted data formats, and consensus algorithms technology. Furthermore, Blockchain’s distributed smart contract technology could be utilized to validate digital signatures and store cryptographic endorsements for future verification, allowing for the safe development of BIM information processes. Furthermore, other Blockchain benefits in BIM could be minimizing information and document redundancy ^[32][91], providing automation in the design process ^[33][129], and post-disaster recovery ^[34][130].

6. Internet of Things (IoT) and Blockchain

The IoT is a vast network infrastructure of numerous interconnected devices that depend on technology for sensing, communicating, networking, and processing information. IoT devices have many advantages, but they also have some drawbacks, such as the fact that they produce a lot of data and use a lot of energy and because they are centralized and controlled by an administrator who can alter the underlying system or even shut it down entirely, which raises trust concerns. With the help of the IoT system, connected devices may monitor their activity and that of their immediate surroundings, exchange this information with one another, and eventually upload their findings to a centralized server ^[35][131]. Radio-frequency identification (RFID) technology, which enables microchips to communicate identifying data to readers through wireless transmission, is a key component of the IoT ^[36][132]. Open BIM defines the information in the construction site, and data sharing for BIM interoperability often uses the Industry Foundation Class (IFC). However, the IoT is a new phenomenon that may help BIM to integrate actual resources with virtual BIM objects using real-time data, making it a fundamental paradigm for creating digital twin (DT) applications that increase construction efficiency ^[27][37][124,133]. Consequently, DT utilized IoT to upgrade BIM in real-time, whereas Blockchain verifies and adds confidence to all data transfers.

7. Blockchain for Energy Efficiency

Accelerating the adoption of energy efficiency initiatives is crucial for accomplishing two goals. First, the Sustainable Development Agenda proposes doubling the worldwide pace of progress in energy efficiency by 2030. Secondly, to meet the Paris Agreement’s goal of keeping global average temperatures below two degrees Celsius ^[38][134]. Hence, another application of BCT could be in the energy sector. Integrating dispersed renewable energy sources into the current centralized energy system presents various problems within the energy industry, which is under change. IoT and BCT are two examples of the digital potential facilitating the development of a decentralized and democratic energy system ^[39][135]. Furthermore, BCT can offer an innovative means of enhancing energy efficiency initiatives’ transparency and lowering transaction costs.