Relative Information Modelling Based Optimization for Asphalt Pavement Renovation

Different possibilities to utilize information modelling and automation in roadway maintenance and renovation, have been studied in Finland during 2010 -- 2014. Mobile laser scanning was used for the initial data surveys. For the surveys and later design and construction phases, there are generally two alternative methods available for the executions: absolute or relative optimization. In the absolute method, coordinates xyz are accurately measured in relation to the used global coordinate system using reference signal points with appropriate intervals. In the design phase, the absolute point cloud enables the geometric optimization of the whole length of the road. In the construction phase, machine control can be done using automated 3-D machine control system in the global coordinate system. In the relative method, coordinates xyz are measured in relation to the existing road surface without using any reference signal points. In the design phase this relative point cloud enables the specific optimization for each of the selected road parts having some unevenness to be fixed. In the construction phase, machine control can be done using a guidance principle, where a human operates the machine and the blade using a tablet user-interface with RTK-GNSS positioning showing the XY positioning of the blade and the needed asphalt fill or milling cut in z direction. The experiments of the relative method were made in real construction projects of Vt6 (Koskenkylä -- Kouvola) and Kt55 (Porvoo) in Finland during 2013 -- 2014. According to the achieved results, the relative optimization method is accurate enough for the renovation needs of local unevenness of roads. It is much cheaper than the absolute method and the material savings are remarkable compared to the traditional method, where no surveyed information is used. The relative method does not apply to the road parts, where absolute geometry dependences are critical.