Bio-based ultra-lightweight concrete applying miscanthus fibers: Acoustic absorption and thermal insulation

Y.X Chen,F Wu,Qingliang Yu,H.J.H Brouwers

doi:10.1016/j.cemconcomp.2020.103829

Abstract

Acoustic and thermal comfort play an important role in the building environment. This study investigates ultra-lightweight concrete incorporating Miscanthus fibers as lightweight aggregates to improve sound absorption and thermal insulation properties. Miscanthus fibers (MF) is a kind of sound absorption biomass that can dissipate sound noise thanks to its porous and flexible inner structures and fibrous shape. However, its acoustic absorption performance in cement-based materials is rarely investigated. Therefore, the acoustic absorption and thermal insulation of ultra-lightweight Miscanthus concrete (ULMC) is investigated using two different kinds of Miscanthus fibers. Meanwhile other mechanical properties were characterized, including bulk density and flexural strength. Results showed ULMC with 30% 2–4 mm MF obtained an ultra-low density (554 kg/m3), thermal conductivity (0.09 W/(m·K)) and high acoustic absorption coefficient (0.9) at low frequencies. It is found that the acoustic performance of ULMC can be improved by optimizing the dosage and shape of Miscanthus fibers. The developed green and sustainable bio-based ULMC possesses an excellent acoustic absorption and thermal insulation and is very suitable to use as indoor ceiling boards and in non-structural walls to make indoor living environment comfortable and energy-saving.

Highlights

As governments and industries are striving to save energy and reduce environmental burden for years, concrete with low carbon footprint and unique functions are attractive and promising for a sustainable society [1,2,3,4,5]
Both 0-2 and 2–4 mm Miscanthus fibers (MF) decrease the flowability of ultra-lightweight Miscanthus concrete (ULMC) as the replacement of MF amount increases
This paper presents the research of developing ultra-lightweight Miscanthus concrete (ULMC) incorporating Miscanthus fibers (MF) and expanded waste glass (EWG), with the extra efforts on the effects of different format of MF on acoustic absorption

Summary

Introduction

As governments and industries are striving to save energy and reduce environmental burden for years, concrete with low carbon footprint and unique functions are attractive and promising for a sustainable society [1,2,3,4,5]. Lightweight concrete (LWC) is a type of cementitious materials with density from 800 kg/m3 to 2000 kg/m3 and has the potential to obtain good thermal insulation and acoustic absorption properties [6,7]. Recent researches have shown bio-based lightweight aggregates like hemp and Miscanthus fibers can function as sound absorption materials in cement and concrete [13]. The results show the hemp fibers itself can greatly absorb sounds and can in crease the acoustic performance of bio-concrete. It is prom ising to hybridize expanded waste glass and plant fibers as lightweight aggregates in LWC to increase the acoustic absorption performance and improve the quietness in indoor environment

Objectives

Methods

Results

Conclusion