## 6 Conclusions  
Removing concrete formwork after a sufficient level of strength has been reached is critical to the quality of the concrete and the consequent safety and health of the structural components. The current study has documented various sensor-based concrete monitoring systems for use during the formwork process. Studies integrating BIM into the concrete formwork process have to date focused on design and planning rather than controlling the project and formwork use. Therefore, this study extended the interoperability of BIM for monitoring the status of curing concrete and computing its maturity and the timing of the formwork during the concrete placement. A sensor module was designed to receive data from three sensors collecting concrete temperature data. The data were conveyed to the associated parts of an objective 3D model via Wi-Fi. A database was then created via the BIM API add-in and based on the concrete's maturity as computed and the formwork removal time, thus assisting the user's decision-making with regards to the concrete work. A 3D model of an active construction project in Iran was established to validate the system. During the case study, sensors were planted in various structural components, columns, beams, floors, and slabs. The data collected by the sensors and module were then transmitted to the designed software. The BIM-based system presented here was capable of receiving and documenting data in real-time. The data computed in BIM were automatically stored in an IFC format. These data were capable of describing the strength of the concrete, building codes, and associated criteria, as well as opportunities to remove the formwork. The results of the case study showed that the concrete formwork could be removed approximately 40% earlier than the documented standard time without resulting in any structural damage.  
In summary, this study proposed a new form of BIM interoperability for concrete formwork control and monitoring. This work ignored natural errors from the sensors, as well as other external factors affecting the concrete formwork. However, it should be underscored that this research provides extended interoperability for managing project activities, particularly concrete formwork, and the developed system can reduce the time spent before removing concrete formworks while still ensuring the concrete's strength. In the future, this BIM-based system could be incorporated with BIM-based concrete formwork design and planning processes described in previous studies to improve the efficiency and productivity of concrete formwork use, as well as reduce redundancy. Other future efforts should investigate the economics of this new system's use, as well as other issues affecting management feasibility. Such efforts will lead to an overall reduction in the time and money consumed by construction projects.  
Conceptualization, M.H. and J.M.S.; methodology, M.H., J.M.S., and S.K.; software, M.M.; validation, M.H., M.M., and J.M.S.; formal analysis, M.H.; investigation, J.M.S. and S.K.; resources, M.M. and J.M.S.; data curation, M.H., M.M., and J.M.S.; writing--original draft preparation, M.H.; writing--review and editing, S.K.; visualization, M.H. and S.K.; supervision, J.M.S. and S.K.; project administration, J.M.S.; All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
The authors declare no conflict of interest.