Evaluation of recycling capabilities of bio-stabilised earth building materials

Cuccurullo, A; Muguda, S; Gallipoli, D; Perlot, C

Abstract

Earth building materials are considered sustainable due to the inherent low embodied and operational energies, the ability to buffer hygrothermal fluctuations and the recycling potential. Despite these advantageous attributes, they are not employed in mainstream construction mainly because of their vulnerability to water. To improve durability in humid environments, earth is often stabilised with chemical binders, such as cement, which results in similar mechanical properties to those of conventional building materials. It has been reported that the addition of about 8-12% of cement to the earth is sufficient to obtain the same mechanical performance of fired bricks1. Cement stabilisation was initially adopted for the manufacture of compressed earth blocks, but it has now become a norm for other forms of earthen construction like adobe. The addition of cement increases durability but also contributes to carbon emissions while increasing embodied energy. Studies have shown that cement-stabilised earthen materials have the same net carbon emissions as lean concrete and, therefore, relatively poor green credentials. Furthermore, cement stabilisation negatively impacts other aspects of material performance by reducing both hygroscopicity and ease of recycling2. Reduced hygroscopicity leads to a poorer ability to buffer hygrothermal fluctuations and, hence, higher levels of operational energy for ensuring adequate levels of indoor comfort. The loss of recycling potential means instead that demolished materials cannot experience a full lifecycle but are either downcycled or dumped in landfills. To reinstate the original sustainability of the material without compromising on durability, it is necessary to look for alternative stabilisation techniques that can ensure engineering performance while retaining hygroscopic and recycling advantages.

Citation

Cuccurullo, A., Muguda, S., Gallipoli, D., & Perlot, C. (2022, March). Evaluation of recycling capabilities of bio-stabilised earth building materials. Paper presented at RILEM International Conference on Earthen Construction, Université Gustave Eiffel, Paris

• Presentation Conference Type: Conference Paper (unpublished)
• Conference Name: RILEM International Conference on Earthen Construction
• Conference Location: Université Gustave Eiffel, Paris
• Start Date: Mar 18, 2022
• End Date: Mar 19, 2022
• Deposit Date: Sep 16, 2022
• Public URL: https://durham-repository.worktribe.com/output/1135408