No abstract

Indonesia is a country with the second-largest amount of plastic waste into sea pollution in the world. The volume of Indonesia's plastic waste imports in 2018 reached 320 thousand tons. To reduce plastic waste, the processing innovations need to be done, and one of them is for building material in the form of a brick. This study used a mixture of plastic waste, sawdust, and rice husk with cement adhesive through a specific ratio. The research aims to test the ability of concrete blocks to absorb sound. The research method used was the test of sound absorption ability by 20 samples of brick making test material. The sound source was generated from the shotgun. Then the sound recorded by the dodecahedron microphone which was connected to Adobe Audacity software. Processing impulse response data used the Real-Time Analyzer program. The concrete test material was made from a mixture of plastic, sawdust and rice husk in a ratio of 30/70, 50/50, and 40/60. The sound absorption test was carried out in an enclosed 3.5x3.5 m 2 acoustic laboratory. The concrete block, which was a mixture of plastic and rice husk with a ratio of 30/70, was the best material for absorbing sound. The sound could be absorbed up to 1.2 decibels, while the mixture of plastic and rice husk with a ratio of 60/40 was the lowest material in the ability to absorb sound. High-capacity concrete blocks could not only absorb the noise but also be used as building space separating materials.