A modular design approach for porous green sound-absorbing concrete for the noise barrier on high-speed railway

Abstract

Recycled aggregate porous concrete is a new type of concrete that saves natural aggregates, realizes the utilization of waste, and has the advantages of environmental protection and sustainability. However, the poor sound absorption coefficient (SAC) and the noise distribution of high-speed railway is not concentrated hinders its application to sound barriers. This study introduces a method of modular design, which includes adjusting the thickness, surface holes design, and modular combination, and the combination strategy of the modules is investigated. In this study, the porous concrete was mainly comprised of tiny and middle ceramsite recovered from waste as aggregate and cement as cementitious material. In order to investigate the effect of holes and modular combination, specimens were drilled holes on the surface, and the diameter of the holes was divided 10 mm and 5 mm. The depth of the holes is varied. The SAC of the sample in the range from 50 Hz to 1700 Hz is tested by the impedance tube and the average SAC of the sample is calculated. In addition, this study applies artificial neural networks to predict the result of the combination strategy. The results show that increasing thickness can improve the SAC of the material at low frequencies, the single module can improve the sound absorption coefficient at specific frequencies by 75%, and the combination of modules can achieve an average SAC of 0.73. The combinations with continuous holes connecting the surface have the best effect. Artificial neural networks can predict this effect accurately. The modular design method in this study provides a solution to the limited application of porous concrete with recycled aggregates.