Federal Highway Research Institute

Measuring equipment

Accelerated traffic simulation using the MLS30

Principle of the MLS30

At BASt, the MLS30 Mobile Load Simulator is used for the realistic accelerated road pavement testing on test surfaces. Four test wheels inside the MLS30 are used to apply a variable axle load of between 45 and 75 kN to the test surface.

The test wheels are contained within bogies which move in a closed chain on rails in a vertical-oval direction, enabling a realistic, unidirectional load to be applied.

Up to 6,000 axle loads are applied per hour, so that significantly more axle loads can be applied than with comparable full-scale accelerated pavement testing equipment.

Sensor technology

For structural monitoring of the test set-up, it is essential to use sensors as well as other measurement methods in the test set-up. The MLS30 loads the road structure with its four load wheels. This load causes a reaction within the road structure, which is detected by integrated sensors, processed and stored for further evaluation. Relevant physical parameters are elongation, compressive stress, velocity and acceleration as well as air and pavement temperature. In addition, additional sensors can be installed to determine further pavement quantities.

Measurement methods

Non-destructive and destructive tests are carried out during the test period. The Falling Weight Deflectometer (FWD) is used to determine bearing capacity values, the Ground Penetration Radar (GPR) to determine layer thicknesses and inhomogeneities and the Profilometer to determine flatness values. Depending on the test program, further methods can be used.

The purpose of destructive tests is to enable material properties to be determined during subsequent laboratory tests, for example when ascertaining the residual service life. This type of test is generally performed after the load operations on areas to which load has or has not been applied.

The picture shows the BASt 3D ground penetrating radar BASt 3D ground penetrating radar