Sustainable Use of Recycled-Glass Powder in Soil Stabilization

This study investigates the performance of sustainable use of recycled-glass powder (GP) in soil improvement. The porosity/cement ratio ($\eta /C_{\mathrm{iv}}$) and curing time are employed to study the evolution of unconfined compressive strength (${\mathrm{q}}_{\mathrm{u}}$) and durability against wet–dry cycles (measuring of loss of mass) of a sedimentary silty soil of Guabirotuba formation, stabilized with GP and cement, in Southern Brazil. Three dry unit weights of molding (${\gamma }_{\mathrm{d}}$), three cement contents ($C$) between 3% and 9%, and curing times of 7, 28, and 90 days are used to study the influence of GP content (i.e., 5%, 15%, and 30% by weight) and $\eta /{\mathrm{C}}_{\mathrm{iv}}$ index on ${\mathrm{q}}_{\mathrm{u}}$ and accumulated loss of mass (ALM) of the compacted blends. The long-term strength improvement and durability are observed and well-fitted to a power function depending on the $\eta /{\mathrm{C}}_{\mathrm{iv}}$ ratio. When ${\gamma }_{\mathrm{d}}$, GP, and $C$ are increased and the initial porosity ($\eta$) is reduced, ${\mathrm{q}}_{\mathrm{u}}$ strength and durability increase for all GP contents. The $\eta /{\mathrm{C}}_{\mathrm{iv}}$ ratio can also establish the empirical ratios between ${\mathrm{q}}_{\mathrm{u}}$-ALM dependent on the GP contents used during compaction of the specimens. Finally, equations for dosing and estimating ${\mathrm{q}}_{\mathrm{u}}$ and ALM are obtained and set to 96.5% with a 6% error. Thus, all strengths and ALM percentages show the same normalized (i.e., divided) potential trend as the functions of GP, $C$, and ${\gamma }_{\mathrm{d}}$, compatible for the value of $\eta /{\mathrm{C}}_{\mathrm{iv}}^{0.20}=37.5\%$ by volume, and it may be possible to extend it to other compacted blends proposed in the recent literature, such as soil-lime and soil-cement-roof tile waste.