Acoustic performance and microstructural analysis of bio-based lightweight concrete containing miscanthus

Miscanthus Giganteus (i.e. Elephant Grass) is a cost-effective and extensively available ecological resource in many agricultural regions. This article aims at a fundamental research on a bio-based lightweight concrete using miscanthus as aggregate, i.e. miscanthus lightweight concrete (MLC), with the special focus on the acoustic absorption property and interaction between miscanthus and Portland cement hydration. The effects of the content, particle size and treatment of fibers on the performance of MLC, including the flowability, strength and acoustical properties, are investigated. Furthermore, the effect of miscanthus on cement hydration is analysed by isothermal calorimetry, X-ray Diffraction, thermogravimetry, and scanning electron microscopy. It is demonstrated that the sound absorption of MLC is dramatically improved with the increasing content of miscanthus. The results show that there is a certain amount of closed internal pores in the composites, which contribute to this enhanced acoustic absorption performance.