Rammed Earth stabilised with waste materials: A sustainable and resistant solution

Earthen dwellings are part of the vernacular architecture and cultural heritage of many countries in the Mediterranean region, and a renovated interest towards these types of structures is now widespread in the same countries mainly due to sustainability reasons. However, poor resistance to weathering compromises their durability and their popular acceptance. A fascinating option to improve the resistance of earthen structures while preserving their environmental sustainability is to use locally available waste materials as stabilisers. In this paper, the evolution over time of the mechanical resistance of rammed earth stabilised with residues from widespread industrial processes (i.e. fly ash from coal combustion and calcium carbide residue from acetylene production) was investigated. Waste-stabilisation prompted optimal long-term mechanical resistance; on the other hand, laboratory samples exhibited low compressive strengths in the short-term when cured under standard conditions. The addition of a supplementary industrial residue (i.e. gypsum from flue gas desulfurization) was explored to enhance the early-age strength. Results confirmed the short-term strength benefits induced by gypsum addition.