Leaching behaviour of stabilised expansive soil with biomass bottom ashes as eco-agents

The search for sustainable alternatives for waste disposition other than disposal and evaluation of the feasibility of a second life cycle for waste should be a priority in the research and characterisation of alternative materials. In civil engineering infrastructure applications (e.g. railway, pipe bending, or road construction), large volumes of aggregate are required, which necessitates the consumption of natural resources and significantly impacts soils and the environment in the surrounding area. Occasionally, when the in situ soil does not possess the appropriate mechanical properties or has low load bearing capacity for traffic or other loads, chemical stabilising agents are used to improve the soil characteristics. However, the development and implementation of sustainable alternatives must become a priority in economic, social, scientific, and technical strategies to address current environmental challenges. This study analyses the environmental viability of using eco-friendly agents instead of the chemical additives traditionally used in soil stabilisation. Based on the findings, it is affirmed that the bottom ashes from the combustion of an olive and grape waste biomass in cogeneration plants possess adequate properties as an eco-stabiliser, are not harmful to the environment, and are feasible as an eco-agent for expansive soils in civil engineering works.