3D texture measurements - visual method for determining the surface properties of road pavements

Low-noise road pavements are used as effective noise abatement measures in Switzerland. To determine the actual effect of low-noise road surfaces, G+P uses numerous measurement methods. While the most common measurement methods record the properties of road pavements acoustically (e.g. with microphones), 3D texture measurements can be used to measure and assess the visual properties of road pavements that are relevant for noise generation. G+P has been carrying out such 3D texture measurements with its own photogrammetry scanner since 2022.

Range of application of 3D texture measurements

In general, the question arises how the surface texture of a road pavement affects the acoustics and how it changes over time. To investigate this, 3D images of the surface texture are generated in addition to the already commonly known CPX acoustic measurements. The figure above shows the results of 3D texture measurements of three different road surfaces. While the profiles of the SDA 4 and the AC 8 pavement show smaller profile differences, several grain peaks are visible in the profile of the exposed aggregate concrete.

Determination of texture parameters

With the help of 3D texture measurements, various texture parameters of the surfaces of road pavements can be collected, such as the mean profile depth, the shape factor or the texture wavelength. The resolution is very high with over 3.5 million points per measurement (approx. 100 points per mm3). Since the surface is recorded three-dimensionally, additional evaluations such as counting grain breakouts and grain peaks can be performed. The results of the 3D texture measurements provide information about the nature of the surface texture and, for example, in combination with CPX measurements, provide valuable information about the acoustic and mechanical condition and changes of low-noise road pavements.

Realization of 3D texture measurements

The 3D texture measurements can be carried out with little effort. The measuring device must be positioned at a height of approx. 20-30 cm above the road surface to be measured. The measurement is triggered by software at the push of a button. For each measurement, an area of the road surface 120 mm wide and 75 mm long is recorded. For each measurement, a 3D texture model is created, which can be viewed on the software immediately after the measurement (see video above). With a measuring device designed by G+P, with which the measuring device is fixed at the necessary measuring height, protected from sunlight, the measurements can be carried out efficiently, which is why several measurements per road surface are possible without any problems.

If you have any questions or uncertainties about our 3D texture measurement system, please feel free to contact our road surface acoustics team :-)