# Reshaping the Digital Twin Construct with Levels of Digital Twinning (LoDT)
## 3 Digital Twinning throughout the Life Cycle of Physical Assets
### Uses and Life Cycle Phases of Physical Assets
#### 3.1.2 Construction  
The construction phase represents the materialisation of the design phase, during which the asset transitions from the virtual space to the physical space.  
Figure 3: Ease of change and incurred cost across the physical asset life cycle (adapted from [50]).  
During construction, costs increase significantly as the asset is brought into the real world (Figure 3). The ease of making changes to the asset decreases and the associated cost rises as construction progresses. Nevertheless, any errors in design or construction still have a relatively lower impact on the asset's life cycle compared to the subsequent phases. The construction sector remains one of the least productive, making the introduction of digital processes and technologies in this phase a promising opportunity for innovation and process transformation. Although the physical asset does not yet exist during the construction phase, the digital twinning of its construction process is still possible. The equipment and labour used in construction can be monitored for various purposes. Monitoring can help fine-tune equipment productivity estimates through data collection, enhance on-site safety by creating alerts or protection zones for workers (digital shielding, [53]), or provide more accurate progress tracking. Additionally, the entire logistics chain can be monitored and optimised. Tracking the arrival of specific materials at the construction site can be used to adjust project planning, communicate with interested parties, and improve the quality of constructed assets. For instance, in concrete pouring, the timing of fresh concrete arrival at the site is crucial for coordinating tasks (like formwork, reinforcement, concrete pouring, inspection, and safety control), as well as for guaranteeing the proper quality of the constructed elements. Once the task is completed, the physical properties of the constructed element can be monitored through embedded sensors in the material. Data such as temperature and strength can be useful for optimising subsequent activities (e.g., formwork removal) and ensuring proper execution of elements. Another example is the monitoring activity of paved roads, where the payer itself reads the pavement temperature and geolocates it for quality control and traceability purposes. Noteworthy examples include the BET4.0 and PAV4.0 demonstrators, developed under the Rev@Construction project [54], which are dedicated to integrated and optimised management of concrete pouring and pavement processes, respectively.  
Beyond the opportunities presented by data collected from construction activities, there are also opportunities associated with other dimensions of digital twinning. Digital modelling of the construction site throughout the various construction phases can aid in site planning. Visual overlay of the design with the actual constructed elements presents valuable opportunities for multiple stakeholders. It serves as a straightforward and transparent means of communication among various parties involved in the construction project and a tool for quality verification and work planning. An example of such initiatives is the PointCloud4 BIM activity of the Rev@Construction project [55], where a point cloud of the built environment is collected and then transformed into a BIM model (as built). This as-built model is subsequently compared with the as-designed model to estimate constructed volumes and analyse progress. These applications can also be highly useful in increasing the accuracy of estimates for the quantity of work and materials actually executed on-site, streamlining and expediting the invoicing of completed work.