## 5 Discussion  
This study proposed a method for expanding the interoperability of BIM with wireless sensors in order to monitor the concrete maturity and control the concrete formwork process. While previous efforts to create BIM-assisted systems focused on concrete formwork design and the planning process, the system developed in this research targeted a concrete formwork control that potentially affects construction management and project controls. Particularly, the extended capability of BIM allows for the calculation of formwork removal time based on the maturity and strength data collected from planted sensors. In the case study, the overall approach, including wireless sensors, concrete maturity, and formwork removal control, was tested at a real construction project. As a result, this study identified the amount of time reduction in the removal of concrete formwork, as compared to the time given in the standard. Based on the case study, this study has four noteworthy implications. First, sensor data can be transmitted to the BIM environment via a Wi-Fi signal with a TCP-IP protocol and API add-in interface. Data related to the concrete's maturity can then be connected to the associated 3D objective model in the BIM environment. Therefore, this system is capable of monitoring the status of concrete and providing maturity data for users of the BIM environment. Therefore, the sensor module and BIM add-in developed in this study contribute to extending BIM's interoperability in terms of real-time concrete monitoring and formwork process control. Second, this interoperable BIM-based system can calculate the removal times of concrete formworks according to different parts of a structure (i.e., slab, beam, or column). This system will help practitioners to continuously monitor and control the concrete placement process and deliver an earlier time to remove the formwork. The current standards manually regulates the recommended time for removing the formwork to maintain the concrete's performance. However, the results of the case study imply that the time for removing the formwork was reduced beyond what was recommended in the current standards. Removing the formwork earlier while still ensuring strength will help to avoid project delays and unnecessary formwork rental expenses. This will lead to reducing the time needed for the concrete formwork process and, consequently, project completion. Third, it can be noticed that the use of BIM can be expanded from the concrete formwork design and layout to the concrete placement control. The previous studies contributed to documenting the design process of the concrete formwork by using BIM. This research described a proof-of-concept to exchange real-time sensor data in the BIM environment. By integrating two concepts in the BIM environment, it can provide more efficiency to design and control the concrete formwork. Lastly, the developed BIM interoperability will help to prevent concrete rework from failing to gain the necessary strength. Based on the case study, the system demonstrated less than a 13%  
Figure 6: Schematic of BIM interoperability for concrete maturity monitoring. difference in concrete strength between the manual and newly developed system-based methods. Also, this implies that using the average temperature data collected from three sensors to calculate the strength and formwork removal time is of low tolerance. Since concrete work can be as high as 40%-60% of the total project cost and concrete formation usually represents over 50% of the entire set of concrete-based tasks in a construction project [59], minimizing the reworking of concrete jobs is very significant for preventing total cost overruns. Consequently, this system will save time and cost on construction projects. In this sense, this new BIM interoperability is beneficial for project control and management of construction.