Absorption properties of green sound barriers

Sammanfattning: This thesis was conducted on behalf of Butong AB, who wanted to test and develop an environmental friendly, so called green sound barrier, which combines both art and science.Different configurations of the product were proposed by the company with various filling materials, as it was predicted that the filling materials would be the main sound absorbent among all parts of the structure.The thesis work started by selecting the best of the proposed fillings which could be of interest - that is those which were expected to have high sound absorption coefficients. The selection process was based on experience, reading and advice. The main idea behind the selection process was saving cost for the company as well as effort.Impedance tube method was used for performing the measurements on samples of the green sound barriers, in order to calculate the acoustical properties of each material and every construction, as it was considerably reliable, cheap and fast to use.The measurements were done according to a combination between standards described in ISO 10534-2:1998 and ASTM E2611-09, for performing test measurements using the impedance tube.This master thesis gives an explanation of the predicted absorption characteristics of the green sound barriers including the usage of different fillings, as well as the advantages and disadvantages of using it in real life applications.