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Bilaga 10Mätning av vägnedbrytning – PercostationPERCOSTATIONPercostation – a Tool for Monitoring Moisture and Bearing Capacity in RoadConstruction, and Optimising the Use of Load RestrictionsCurrently, transport corridors are needed year-round for deliveries to industry andtrade. Long breaks in traffic connections are not tolerated, and the costs of a shortdelay or minor load restriction multiply throughout the stream of production; inFinland the costs of one day of load restrictions have been calculated to amountto approximately € 600.000. On the other hand, as the budget for road maintenancehas been reduced, the road owner has an increasing need to protect roadswith low bearing capacity e.g. with load restrictions.One way to better manage the dilemma is to monitor the behaviour of the roadstructure during sensitive seasons, and to optimise the use of load restriction.During the last 10 years the deformation properties of road aggregates and theirrelation to electrical properties have been studied intensively in Finland and theUSA. The results of these studies show a clear connection between high dielectricvalues and the susceptibility to permanent deformation. Electrical conductivityhas also been found to provide valuable information concerning pore water in amaterial.This provides a basis for effective monitoring systems for seasonal changes in thebearing capacity of roads, which enables the imposing of load restrictions basedon real-time measurements instead of visual estimation.EquipmentRoadscanners has developed, in cooperation with the Estonian Adek Ltd, thePercostation; a system for the monitoring critical bearing capacity. The systemconsists of sensors installed in a problematic road section, at different depths inthe road structure and subgrade soil; a data collecting unit installed roadside; anddata transfer and analysing systems, which transfer the measurement results viagsm network or telephone cable to the pc screen of the road authority, for use inload restriction planning.Technically, the Percostation deviates from the Percometer in so far, as it enablesmeasurements of dielectric value, electrical conductivity, and temperature fromeight channels. The measurement interval can be set to a minimum of 60 seconds(four channels). The measurement results are stored in the memory of the datacollectionunit, where they can be read through a modem connection. Thememory of the collection unit is sufficient enough to store 360 measurements atonce. The settings of the data-collection unit can also be modified through themodem connection.87ETT-Modulsystem för skogstransporter