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

Abstract

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.

Synergistic effect of surfactants in porous geopolymer: Tailoring pore size and pore connectivity

“…Several studies were focused on the acoustic characteristics of direct-foamed alkali-activated materials [94][95][96][97][98]. Peceño et al [99] stated that the materials with larger total porosity absorb sound better because the sound penetrates their matrixes and dissipates the sound energy. Moreover, open pores generate continuous pathways between the interior and outside of the material matrix, resulting in enhanced permeability and good sound-absorption capacity.…”