Eco-efficient mortars from tunnel excavated soils for wall panels: Performance enhancement and life cycle evaluation
Year: 2025
Type: article
Abstract: Valorizing the millions of tonnes of tunnel excavated soil (ExS) from urban mega-projects like the Grand Paris Express is a critical challenge for the circular economy, while the construction sector simultaneously seeks low-carbon alternatives to conventional finishing materials. This study pioneers a holistic approach to upcycling ExS into mortars for sustainable products (wall panels), by systematically comparing conventional (CEM I, slag) and novel biopolymer (tannin) stabilizers combined with hemp fibers across fourteen formulations. The tannin-stabilized formulation (Mix10: 5% CEM I, 2% tannin, 0.8% hemp) achieved an optimal balance of properties, with a 28-day compressive strength of 0.85 MPa and a low thermal conductivity of 0.459 W/m·K. A cradle-to-gate Life Cycle Assessment (LCA) revealed that slag-based mortars (M4) reduced the Global Warming Potential (GWP) by 96% compared to conventional gypsum mortars, and by 44% compared to reference ExS-based cement mortars (M2). By introducing and validating a CO₂ intensity index for earthen mortars, this work provides a new benchmark for evaluating eco-efficiency. The findings demonstrate that ExS mortars can be upcycled into panels that are both technically proficient and environmentally superior to market alternatives, offering a scalable solution for sustainable urban construction.
Language: English
Subfield: Building and Construction
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,540
OpenAlex ID: W4416796028