Morphological analysis of porosity and sound absorption in sustainable materials from rice husk

This study proposes a composite material that incorporates rice husk. This research focuses on an experimental analysis of the physical, mechanical and acoustic performance of composite materials made of rice-husk waste. Various ratios of rice husk/resins have been employed. Complementary, X-ray computed tomography technique has been used to characterise a representative and extensive volume of material at the pore level, ranging from pore sizes of 100 μm to several millimetres Furthermore, detailed information of key factors of pore properties inside the matrix (pore size, sphericity, position, tortuosity and permeability) has been provided. All the compositions present high sound-absorption coefficients, with noise-reduction coefficients ranging from 0.39 to 0.52, and suitable compressive strength (>1 MPa). From the results, when the rice husk/resin ratio was decreased, the pore size fell between 1 and 4 mm, and the permeability reduced; in contrast, the compressive strength increased, although the sound absorption capacity diminished.