Comparison of the insertion loss of diffusive noise barriers using scale model experiments

Abstract

A new design of an environmental friendly noise barrier was suggested which can be assembled by unit blocks. It was anticipated to decrease of noise levels because the shape of the blocks is so diffusive that it may reflect and diffuse the sound. The unit blocks also contain the soil and vegetation for landscape which can contribute the noise control as well. Four different designs of noise barriers were suggested considering various practical conditions of construction. In order to investigate the acoustical performances of the various diffusive noise barriers, different size of unit block including 30, 25, 20 and 15cm were introduced. 1/10 scaled models were made and the insertion loss of each model was measured in an anechoic chamber. Also, the difference of diffusive and flat surfaces of noise barriers was analyzed. As a result, it was found that there is no difference of insertion losses depend on the distance from the noise barriers. It was also revealed that the diffusive noise barriers have larger insertion loss than flat noise barriers. And the bigger the unit block is, the larger noise insertion losses were acquired.