Acoustics — Measurement of sound absorption properties of road surfaces in situ — Part 1: Extended surface method
Normal incidence is assumed. However, the test method can be applied at oblique incidence although with some limitations (see Annex F). The test method is intended for the following applications:
— determination of the sound absorption properties of road surfaces in actual use;
— comparison of sound absorption design specifications of road surfaces with actual performance data of the surface after completion of the construction work.
The complex reflection factor can also be determined by this method.