Life cycle assessment for soil stabilization dosages: A study for the Paraguayan Chaco

Geotechnical engineering can account for a considerable portion of the environmental impact in infrastructure and construction projects. As a result, sustainability is increasingly becoming a key research topic in this area. This paper assesses the environmental impact of clay-lime blends for the Paraguayan Chaco region. More specifically, it compares distinct dosages to attain a target strength (unconfined compressive strength and splitting tensile strength) and stiffness (initial shear modulus) using life cycle assessment (LCA). Seven impact categories were considered: acidification, eutrophication, photochemical oxidation, depletion of abiotic resources, stratospheric ozone depletion, global warming, and embodied energy. For all target values of strength and stiffness examined, low-binder/high-density dosages have a lower impact across all categories compared to high-binder/low-density dosages. More specifically, minimal impact across all categories is attained when the smallest binder content (required to attain a target strength or stiffness) is used. Changes in binder content and density produce major increases in three categories: energy consumption, global warming, and photochemical oxidation. Lime production accounts for more than 75% of the total energy, greenhouse gases emission, and photochemical oxidation for each of the blends examined. This supports previous research, which shows that materials accounts for a considerable part of energy consumption in geotechnical works. As a result, minimizing binder content and maximizing density are main strategies to create more sustainable dosages for soil stabilization.