Studies on the sound absorption characteristics of porous concrete based on the content of recycled aggregate and target void ratio

This study performed an evaluation of the physical and mechanical properties and sound absorption characteristics of porous concrete. Design was based on the target void ratio and the content of recycled aggregate. The objectives are to reduce noise generated in roads, railroads, residential and downtown areas as well as to utilize recycled waste concrete aggregate. The test results demonstrated that the difference between the target void ratio and the measured void ratio was less than 1.7%. The compressive strength reduced rapidly when the target void ratio and the content of the recycled aggregate exceeded 25% and 50%, respectively. The sound absorption characteristics of the porous concrete using recycled waste concrete aggregate showed that the Noise Reduction Coefficient (NRC) was optimum at the void ratio of 25% but the percent content of the recycled aggregate had very little influence on the NRC. Therefore, the optimum void ratio is 25% and the recycled aggregate is 50%.