Application of Unmanned Aerial Systems for Progress Monitoring of Pavement: A Case Study

Abstract: The use of UAS (Unmanned Aerial Systems) in the inspection, monitoring, and volume measurement of structures and infrastructure has recently increased, particularly in terms of inspection and construction activities. Monitoring project safety, progress, and material costs is a key responsibility of project engineering and is typically performed daily. Daily monitoring takes a significant amount of time for project engineers to track all the evidence and make decisions in real time. This process becomes more challenging when the engineer is unable to be present on-site continuously. UAS technology has been utilized to document project progress bi-weekly within the industry; however, application of UAS to monitor paving construction progress in previous research were limited to inspection and monitoring in paving. In this case study, UAS was employed to monitor the progress of paving in highway. Elevation and thickness differences in pavement before and after paving were estimated using 3D models in PiX4D to demonstrate the capabilities of UAS and Pix4D in tracking project advancement. To do this, several flights were conducted before and after the lifting of each layer, and 3D models constructed based on the data from these flights from specified location of project. Several fixed segments were selected in all 3D models based on known X and Y coordinates. Random points with the same X and Y coordinates across all models in road were then chosen to measure the thickness between the road and the paving. The results from the 3D models indicate that paving thickness increased by approximately 1 to 2 inches after each round of paving at these fixed points. This demonstrates that project engineering can track changes in the project using these data points, as the only variable that changed between point clouds in 3D models was the Z values, reflecting the thickness of the paving. Moreover, UAS were flown over specific segments of the project to assess the speed of paving (actual work) compared to the project timeline. The speed of construction activities per mile was measured and compared to the established project plan using UAS videos and mileage data. The UAS video and images related to the mileage show that 115 actual hours were required to complete the paving for 11 miles (the total length of the project), with 11 days of work at 10-hour shifts. Compared to the schedule, there was a 20-day delay due to technical issues and weather conditions for finishing the paving.
Keyword: UAS, construction monitoring, PiX4D, Paving, speed of project