Determination of the acoustic characteristics of a gabion noise barrier

In recent road construction projects in NL more and more stone gabions are used as noise reducing measure. First measurements on noise characteristics on gabions using EN 1793-5 showed peculiar results for sound absorption. This was thought to be an effect of the thickness of the gabion and due to scattering of the sound on the non-flat surface. A new investigation was done on stone gabion NRD's and on a regular reflective and absorptive NRD. Focus was on the applicability of EN 1793-5 for determination of the sound reflection characteristics of gabion NRD's. This paper shows the results of measurements on gabion and "regular" NRD's, and of model simulation of these measurements to understand the results, and give guidance on modeling a gabion NRD in a general TNM.