Kvalitetskontroll av överbyggnader med georadar

Nordic countries have been pioneers in ground penetrating radar (GPR) applications on roads. The first applications have been reported in the early 1980´s from Denmark and Sweden. In Finland subgrade soil and road structures have been analysed with GPR for almost thirty years and it is a routinely used tool in the Finnish Traffic Agency’s rehabilitation projects. This GPR method description guideline for road construction quality control projects has been produced, because it is essential that current practice is described precisely so that new entrepreneurs will know how the ground penetrating radar surveys should be done and what the basic quality level for the results should be. There is also a need to specify separately the procedures that should be followed in two dimensional (2D) and three dimensional (3D) GPR quality control survey projects. The results of a quality control survey can lead to, in the worst cases, major economic sanctions against the contractors and therefore the reliability requirements of the results are extremely high. Results have to be repeatable and outputs must be made in a way that eliminates all forms of speculation and/or manipulation of the results. In other words, results have to be waterproof and fair to all interested parties. This method description guideline should be used when doing survey design, data collection, analysis and reporting with the 2D and 3D GPR systems in road construction quality control projects. In this publication, there is also an exact description of how the project results should be linked to road registry data bases or other GIS systems used in Nordic Road Administrations. Pertaining to the parts and methods not described in this publication, the other national publications and guidelines related to road construction quality control / quality assurance projects must be followed. This publication also presents a short introduction to GPR theory and principles. The guidelines were written to meet the general guidelines and practices in the Nordic region but this document can also be used elsewhere in the world. This guideline does not provide a description for the use of GPR technology in asphalt air voids content measurement. This technique is described in another guideline document published by the MaraNord project