Performance of Alkali Activated Slag Stabilized Landfill Mined Soil-Like Fraction Exposed to Different Climatic Conditions
Authors :- AS Reddy, KKR Iyer, VM Rotte, TN Dave
Publication :- International Journal of Geosynthetics and Ground Engineering, Springer 2024.
Landfill mined soil-like fraction (LMSF) is the material obtained from mining of old waste. Utilization of LMSF in infrastructure applications is limited due to several challenges including possible presence of organic content, heavy metals, heterogeneous composition, etc., and require stabilization prior to usage. In light of this, LMSF was stabilized with alkali activated slag at different curing temperatures including freeze curing (− 21 ℃), ambient curing (25 ℃), thermal curing (60 ℃) and their combinations. Further, the performance of stabilized LMSF was evaluated on cyclic exposure to different climatic conditions, viz., − 21 ℃, 0 ℃, 10 ℃, 25 ℃ and 45 ℃ in both closed (without water exposure) and open system (water inundated) conditions. The performance of stabilized LMSF under these climatic conditions was evaluated through unconfined compressive strength (UCS), indirect tensile strength, cyclic loading tests, and microstructural aspects. Based on initial trials, ambient curing (25 ℃) and 2 days thermal curing at 60 ℃ yielded better performance of stabilized LMSF. The 28 days stabilized LMSF has shown stable performance against cyclic exposure to different climatic conditions by satisfying the maximum allowable mass loss criteria after 12 cycles as per IRC-37, except for exposure to subfreezing temperature of – 21 ℃ in open system. Further, not much reduction in UCS and indirect tensile (except for − 21 ℃ in open system) strength was observed on cyclic exposure to different climatic conditions, inferring the stability of cementitious compounds and resistance against degradation. 2 days of thermal curing at 60 °C notably enhanced the performance of stabilized LMSF in different exposure conditions under both static and cyclic loading conditions, suggesting it as favourable curing condition for sustainable and low-cost stabilization of LMSF in different climatic conditions ranging from sub-freezing to arid regions.