This paper presents a case history of Highway 21 from North-Western Finnish Lapland where a new road analysis technique was successfully used in a road rehabilitation design project. This road analysis technique is comprised of the evaluation of subgrade related problems, the condition of unbound and bound pavement structure, drainage and local damage, such as settlements. The analysis was based on ground penetrating radar (GPR) measurements with 500 MHz ground coupled antenna and 1.0 GHz air coupled antenna and other non-destructive test (NDT) methods together with supporting information gathered from core samples, frost probe data, rutting and roughness information, FWD measurement data and GPS data. Visual pavement distress evaluation data and other reference information, such as video images from the road, are also used in the road analysis. Road analysis data and statistical data is then used in the precise rehabilitation design of the road structure, to meet the modern highway geometry and structural standards and specifications. The goal was also to improve the cost-benefit ratio of the project as much as possible in order to get public funding for the project. The analysis clearly showed the reasons for the defects on the existing road and also provided useful information about structures that have performed well in the road. This information was then applied in the rehabilitation design. Special rehabilitation structures were designed for each road environment. The results of this project showed that major savings can be achieved by using this form of analysis and precise rehabilitation design techniques without making major compromises to road quality. The total rehabilitation costs of the project were reduced from 53 million FIM to 23 million FIM. (a)
Abstract