Life-cycle assessment of novel geopolymer stabilization method in applications with expansive subgrades
研究了一种用稻壳灰替代硅酸钠的新型地质聚合物稳定膨胀土的方法，通过生命周期评估发现其环境性能比传统地质聚合物改善约43%，成本效益提高31.5%，对寻求低碳路基处理方案的工程师有参考价值。
Expansive soil, characterized by volumetric changes, presents formidable challenges to road infrastructure. The limitations of Ca-based treatments have spurred the investigation of geopolymers, yet Na 2 SiO 3 in the alkaline activator compromised the sustainability. In response, a novel waste-derived rice husk ash (RHA)-based silicate solution was introduced for geopolymer-based expansive subgrade stabilization (Slag-RHA-GP), though its environmental sustainability remains unexplored. This study conducts a cradle-to-construction life-cycle assessment of Slag-RHA-GP while comparing results with cement (OPC) and conventional Na 2 SiO 3 -based geopolymer treatment (GP) based on a hypothetical case study. Normalized mid-point impacts indicate that the Slag-RHA-GP binder exhibits ∼ 43 % improved environmental performance compared to GP. RHA-silicate substitution reduces ecosystem impacts by ∼ 79 % at the raw material production stage. Moreover, except for Hg and Se, heavy metal leaching of Slag-RHA-GP remains well below permissible levels. Slag-RHA-GP demonstrated a 31.5 % cost-effectiveness and an overall sustainability advantage of 28.9 % and 6.4 % over conventional GP and OPC, respectively. The findings will support the future adoption of sustainable geopolymer stabilizers for in-situ expansive subgrade treatment, aligning with emission neutrality goals.