Oral Presentation Fourth Biennial Australian Industrial Hemp Conference 2024

Acoustic and thermal performance evaluation of low carbon binder Australian Hempcrete (#32)

Siddharth Girish Nair 1 , Mahmoud Karimi 1 , Quang Dieu Nguyen 1 , Yixiang Gan 2 , Xu Wang 2 , Danielle Moreau 3 , Peter Irga 1 , Cecilia Gravina de Rocha 1 , Fraser Tropy 1 , Sara Wilkinson 1 , Arnaud Castel 1
  1. UTS, Ultimo, New South Wales, Australia
  2. University of Sydney, Sydney, New South Wales, Australia
  3. UNSW, Sydney, New South Wales, Australia

Acoustic and thermal performance evaluation of low carbon binder Australian Hempcrete

 

Nair S.G.1*, Karimi M.1, Nguyen Q.D.1, Gan Y.2, Wang X.2, Moreau D.3, Irga P.J.1, Gravina da Rocha C.1, Torpy F.R.1, Wilkinson S.J.1, Castel. A1

1School of Civil and Environmental Engineering, University of Technology Sydney (UTS), Sydney, NSW 2007, Australia.

2School of Civil Engineering, University of Sydney, NSW, Australia.

3School of Mechanical and Manufacturing Engineering, UNSW Sydney, NSW, Australia.

* Corresponding author, e-mail: Siddharthgirish.Nair@student.uts.edu.au

Abstract

Hempcrete is a suitably a promising carbon negative bio-based sustainable alternative which the Australian construction industry can rely upon. Many studies have been carried out to improve the properties of hemp-lime compositions to address the Net Zero Emissions goal. However, lime-based binders are carbon intensive. There is very minimum or close to no experimental studies conducted on low carbon binder options such as calcined clay and geopolymer binders and their potential to be used in hempcrete as a wall material for sustainable dwellings. This initial experimental work tries to explore the acoustic performance and thermal conductivity of different combinations of low carbon binder Australian hempcrete mix designs. For acoustic performance, both absorption coefficient and weighted sound reduction index (Rw) for wall panel applications are investigated. The acoustic tests are conducted in mainly two different manners. Firstly, the absorption coefficient is determined with small hempcrete samples using the standard impedance tube. Secondly, the weighted sound reduction factor (Rw) is calculated by testing hempcrete panels in a sound transmission loss suite. The overall acoustic performance of hempcrete with Calcined Clay or geopolymer binders is improved compared to hydrated lime reference hempcrete. The thermal conductivity of the geopolymer and calcined clay hempcretes is reduced compared to the hydrated lime reference hempcrete. This study shows that low carbon binder hempcrete can comply with standard acoustic recommendations laid down by the National Construction Code (NCC).

Keywords:  Australian hempcrete; Acoustic performance; Thermal conductivity; Transmission Loss, Calcined Clay; geopolymer; Weighted Sound Reduction Index