SCRIM-test vehicle - Determining the friction value of road surfaces
Roughness and the pavement grip of road surfaces are among the user-relevant surface properties, which are contributing for the practical value of the road. The condition and pavement grip of the road surface can be derived from this friction value. The grip test is used in the context of the condition collection and evaluation of road surfaces to test new build roads as well as for statistic evaluations.
6 vehicles are already equipped with our standardsoftware  .
In order to be able to determine the so-called friction value of road surfaces while driving, the lateral force is measured by attaching an additional, mechanical tilted (certain angle to the straight road) solid rubber wheel to the vehicle.
This measurement principle is called SCRIM (Sideway Force Coefficent routine Investigation Machine). The quotient from the measured lateral force and the given wheel load results in the sideway force coefficient. Some correction is done to get the accurate values.
The following data are recorded while driving and calculated to an accurate friction value:
- roadway temperature
- ambient temperature
- water temperature of the water, that is squirted before the solid rubber tire to minimize the resistance for the wheel. The necessary water is carried in a tank. Depending on the tasks as well as on the resulting measuring speed the water is brought immediately in front the measuring wheel on the roadway.
- speed (40, 60, 80 km/h)
- driven distance
- exact position of the vehicle by means of GPS
The sideway force coefficient depends further on the drift angle, on the used tire, its temperature, on the water film height, on a possible lubricating film and the characteristics of the roadway surface. The measuring data is integrated at the exact position as color scale on ATKIS topographic maps.
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