Improving rammed earth walls' sustainability through life cycle assessment (LCA)

Rammed earth, an ancient construction technique based on compacting soil in progressive layers into formwork, has recently seen renewed interest due to its low environmental impact compared to traditional wall systems. However, the choice of the soil and the addition of stabilisers to improve material durability and strength could jeopardize these environmental benefits. Stabilizing earth is very common in Australia, where rammed earth housing accounts for an important share of the new build market.
The focus of this paper is the lifecycle environmental impact of a typical rammed earth building in Perth, Western Australia. The goal is to estimate variation in the structure’s sustainability according to the materials used. Several soil mixtures, conventional and innovative ones, as well as recycled and waste materials (e.g. recycled concrete, fly ash and carbide lime) were considered for the analysis. Durability tests were performed to compare specimen’s mechanical performance and their resistance to erosion. The sustainability analysis of the building material is therefore extended from the construction phase to the entire lifecycle, as recommended by the LCA standards. Results indicated that the choice of the mixture’s components and their source could significantly affect the overall environmental performance of the structure. Even though every soil has different characteristics, similar materials to the ones considered here could be sourced anywhere and the results could be adapted to different geographical areas.