Rice straw stems reveal higher sound absorption coefficient than crushed rice straw: a sustainable approach to the recycling of rice straw

Burning straw openly in fields destroys beneficial soil microorganisms, accelerates soil degradation and generates harmful greenhouse gases. Conversely, finding green materials for noise reduction in buildings is a crucial research area. The research objective was to find an approach that improves the reuse of rice straw to help develop sustainable land and the environment. Primarily, rice straws were crushed to make porous composite boards for sound absorption applications. In contrast, the hollow space of rice straw, a crucial feature of sound absorption, is lost. An investigation was undertaken to measure the sound absorption characteristics of crushed rice straw, rice straw stems, and their mixture (wt%). The sound absorption coefficient was measured using two microphone impedance tubes in 250–6400 Hz. The results showed excellent average sound absorption coefficients for stems at 2000 Hz (0.981 ± 0.019) and 0.994 ± 0.007 at 2152 Hz. The noise reduction coefficient was about 0.389 ± 0.010 for rice straw stem. T-test results (p = ≤ 0.005) indicate a significant variance of SAC of stem samples compared with crushed straw. Furthermore, the findings could stimulate the reuse of rice straw, which would help farmers, land, the environment, and the acoustic house environment. Graphical abstract: [Figure not available: see fulltext.]