Lime stabilization of excavated clayey soils for trench reinstatement: a sustainable recycling case history

In the context of a progressive depletion of virgin construction materials, more and more construction companies are moving towards the production of recycled materials to sell them for different purposes (e.g., infrastructural works, trench reinstatement). The aim of this thesis is to investigate the recycling history of a construction company, i.e., CEA – Cooperativa Edile Appennino, and propose a solution to use the soil stored at the recovery plant of CEA (i.e., CEA Ambiente) for trench reinstatement operations. Excavated soil, coming from waste disposal through sieving operation represents the most abundant material stored at CEA Ambiente, it is usually disposed as a waste (expensive operation) due to its undesirable geotechnical and mechanical properties. The proposed solution is to improve soil characteristics with lime stabilization method carried out inside CEA plant boundaries. A detailed study is then carried out, supported by cost analysis and laboratory tests. Satisfactory results are achieved compatibly to the limitations imposed by the reference Italian standard for soil stabilized with lime (i.e., CNR BU 36 – Soil stabilized with lime).