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 mu m 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 4mm, and the permeability reduced; in contrast, the compressive strength increased, although the sound absorption capacity diminished.