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This study presents a sustainable geopolymer grout for geomechanical applications using recycled ceramic powder (RCP) and nano-zeolite (NZ), activated with recycled lime waste (RLW) as a low-carbon alternative to conventional alkaline solutions. Clayey soils with plasticity indices (PI) of 10.5–65.3 were examined to represent diverse geotechnical conditions. Laboratory tests included flowability, unconfined compressive strength (UCS), pull-out resistance, and stress–strain response under curing temperatures of 25°C and 50°C and saturation degrees of 0–100%. Special attention was given to the capillary saturation range (50–80%), which caused sharp reductions in strength and stiffness due to suction collapse and gel degradation. The optimal grout (30% RCP, 1% NZ, 20% RLW, A/P = 0.5) achieved flowability above 125% and UCS up to 31 MPa at 28 days, exceeding FHWA standards and showing superior thermal stability compared with ordinary Portland cement grout. Microstructural analyses (SEM/XRD) confirmed denser N-A-S-H/C-A-S-H networks with lower porosity. Random Forest modelling (R2 > 0.90) identified PI, curing time, and saturation as dominant predictors of strength. The combined experimental, microstructural, and data-driven findings highlight RLW as an efficient activator and demonstrate the potential of RCP – NZ geopolymers for durable, low-carbon soil stabilisation in geomechanics and geoengineering.
Khanghah et al. (Mon,) studied this question.