Determining the sound absorption coefficient of bagasse using the Two-microphone transfer function method

Noise pollution is ranked as the third environmental pollution that can interfere with communication, recreation, or concentration. Hence, choosing the best materials could be one way to resolve a sustainable solution for noise pollution problems. Materials like bagasse are suitable composite materials for construction. Its natural fiber properties exhibit a good absorber characteristic that would be used for acoustics barriers. Thus, this study aimed to investigate the sound absorption of bagasse using the two-microphone transfer function method. Using two different thicknesses for the samples, 2.0 cm and 4.0 cm, the measured sound absorption coefficients were considerably higher than the conventional concrete. The measurements revealed that the 4.0 cm samples exhibited better sound absorption behavior between the two thicknesses, having a noise reduction coefficient (NRC) of 40% to 80%. It can be noted that it has shown consistency in the energy absorption throughout the frequency range of 250 Hz – 3000 Hz. Meanwhile, for the 2.0 cm-thickness samples, bagasse's performance is less absorptive from 250 Hz-1000 Hz but becomes more absorptive as it goes to higher frequencies with a peak value of approximately 95%. Also, the material's density and the sample's thickness influence the measured sound absorption coefficients. The result implies that bagasse, a green waste, can be a suitable candidate for acoustic building applications. Its advantages included low-cost materials from renewable sources, non-toxicity, and comparably high performance compared to standard or commercial products. These types of barriers can positively impact the noise level in the areas.