Durability, Strength, and Stiffness of Green Stabilized Sand

Waste glass is a solid residue widely available in the urban centers, where it is discarded after being used in the most diverse applications (container for distinct products, tableware, decorative objects, civil construction, and the automobile industry). Carbide lime is a by-product from the manufacture of acetylene gas. This study evaluates the potential of combining these two wastes, finely ground waste glass and carbide lime, as a possible hydraulic cement (substituting portland cement) to enhance soil behavior. Such blends, when compacted, have potential application in earthworks such as beds of pipelines and spread footings, as well as base/subbase of pavements. Pozzolanic reactions occur between silica in amorphous phases (in ground waste glass) and ${\mathrm{Ca}}^{++}$ (in carbide lime) in an alkaline environment. The impact of the ground glass and the carbide lime content, as well as the dry unit weight, on the properties (strength, stiffness, and durability) of compacted sandy soil–ground waste glass–carbide lime mixes is quantified, where two soils have been used, Osorio sand and a clayey sand, Botucatu residual sandstone (BRS). A novel parameter, named the porosity/binder index ($\eta /B_{iv}$), allows normalizing the behavior of the unconfined compressive strength ($q_u$), the shear modulus at small strains ($G_0$), and the accumulated loss of mass (ALM) (after wetting-drying cycles) of the sandy soil–ground waste glass–carbide lime mixes, considering ground glass plus carbide lime as binder. Results have shown similar trends among $q_u$, $G_0$, and ALM with $\eta /B_{iv}$ for the two studied sandy soils–ground glass–lime mixes, even though each was cured at an ambient temperature ($23\pm 2°\mathrm{C}$), but considering different curing periods (7 days for the former and 180 days for the latter).