Weathering's beneficial effect on waste-stabilised rammed earth: a chemical and microstructural investigation

The most common method to improve the mechanical properties of a rammed earth mix is to add chemical stabilisers like cement and/or lime. Varying the stabiliser type will affect strength gain but also the environmental impact. In this paper, the effect of wetting-drying cycles on the long-term unconfined compressive strength of stabilised rammed earth (SRE) mixes was investigated through the chemical characterisation of the soil components and microstructural analyses. The mixes were stabilised using different agents characterised by distinct environmental impacts, such as cement, calcium carbide residue and fly ash. These last two are considered waste materials, significantly affecting their use's associated environmental implications. The results of this experimental campaign support others in this series of work and showed an improvement of the mechanical properties after cyclic wetting-drying due to the formation of new hydration products which bound particles together. The use of waste materials proved to be an effective solution to stabilise RE.