Fabrication of green composites by waste coconut shells as partial replacement of coarse aggregates in concrete and determination of its acoustic behaviour

Abstract

Nowadays, natural materials have been frequently used for sound absorption in constructions and buildings. This paper has characterised the acoustic behaviour of coconut shell reinforced concrete composite with partial substitution of coarse aggregates in terms of sound absorption at octave frequency signals (32 Hz-16 kHz). Composites have been prepared in different weight percentages (5%, 10%, 15%, and 20%) of partial substitution of coarse aggregates. The acoustic test has been conducted in a 3.5 mm thick glass box without and with samples by point method of sound power measurement. The results have demonstrated that the value of the sound pressure level has decreased at different points with the increased percentage of coconut shells in composite, hence increasing the sound absorption coefficient of the concrete. The results have also been compared with conventional concrete composite. Additionally, the results have indicated that these concrete blocks can significantly absorb sound in the mid-frequency range. Generally, a sound absorption coefficient greater than 0.2 for any material qualifies it as a sound-absorbing material, and a sound absorption coefficient greater than 0.6 for any material is known as the best sound absorber. Therefore, developing such green composites can be an eco-friendly approach to the acoustic community.