# Construction 4.0: A Systematic Review of Its Application in Developing Countries
## 1 Introduction  
The presence of humans and their activities in the industrial environment has significantly impacted the construction industry [1]. Material, energy, and control technologies are the three key areas, broken down into their respective categories, that describe the core components of the technological revolution [2]. Because of their influence on human perception, cognition, and overall experience, these domains are responsible for determining how created things perform and the power processes that drive them. By using these spheres, it is possible to create a whole new way of life.  
Before the 19 th century, there were restrictions on the variation of materials, which imposed engineering limits with regard to the weight, height, and strength of structures. These materials included both man-made and natural materials such as wood, stone, lime mortar, and concrete [1]. The first industrial revolution began in 1760 and lasted until around 1830. During this time, the mechanical heavy industry had a phenomenal growth spurt. As a consequence of this progression, a wide variety of new cutting-edge construction materials came into being. Glass, cast iron, and steel were some of the materials that engineers and architects developed to produce buildings that defied traditional conceptions of form, construction, and usefulness [3].  
The year 1870 marked the beginning of the second industrial revolution (electricity), which was characterised by a high concentration of innovation.  
These new innovations involved using practical knowledge to make technologies that could produce steel, electricity, telegraphs, and railroads quickly and at a lower cost.  
The transformation in question compelled those working in the construction sector to pioneer new ideas in the fields of architectural design and the optimisation of vertical space--building taller and deeper [4].  
In the middle of the 1980s, the introduction of computers and the internet led to a big change in how technology was used. This revolution included the digitalisation of mechanical and analogue processes in addition to a move away from mass manufacturing and towards mass customisation. The advent of this third industrial revolution spawned fresh interactions between architecture and technology, which proved to be a significant obstacle for the manufacturing sector [5]. Architects began using dispersed three-dimensional computer-aided design software as a representational tool to increase the accuracy of their designs and widen the extent of digitalisation.  
Using computer-controlled manufacturing processes, known as CNC [6], made it possible to create complex shapes that would have otherwise been impossible to make. These techniques use a series of instructions in code to regulate the movement of a machine tool. The use of CNC technology made it easier to combine 3D-CAD models and computer-assisted manufacturing (CAM) processes [6]; subsequently, this opened the door for the mass customisation and computerisation of the production of building parts. Advanced construction techniques seemed to be less efficient and more difficult to create due to the advancement and growth of digital fabrication and digital architectural technology [6]. This set the stage for the fourth industrial revolution, Industry 4.0, which is explored in this article from a construction standpoint, referred to as Construction 4.0. Whilst there is current debate around Industry 5.0 (focused on humans and artificial intelligence working together) and Construction 5.0 (suggested to accelerate both the green and digital transitions, setting the stage for a more resilient and sustainable society and economy), this is beyond the scope of this current publication [7]. Moreover, it is beyond the current scope of inclusion in many developed, never mind developing, countries.