Eco-friendly compressed earth blocks stabilized with basalt powder: Mechanical, thermal and environmental assessment

The transition toward greener construction practices calls for innovative material solutions that reconcile structural performance, thermal comfort, and environmental responsibility. In this context, this study investigates basalt powder (BP), used as a standalone mineral stabilizer for compressed earth blocks (CEBs). Basalt powder and soil were characterized by XRD, SEM, and FTIR, and CEB specimens were prepared with BP contents ranging from 0% to 20%. Results show that BP incorporation improves particle packing, increasing density and reducing porosity up to 15% BP, corresponding to a maximum dry compressive strength of 5.43 MPa (+36.8%), before decreasing at higher dosages due to excessive fine-particle agglomeration. Thermal conductivity decreases continuously with BP content (−15.8% at 20% BP), while thermal inertia improves, as reflected by reduced diffusivity, effusivity, and damping factor. From an environmental standpoint, a comparison with a cement-stabilized reveals an 83% reduction in embodied carbon for the optimal formulation (CEB-BP15), confirming basalt powder as an effective pathway toward more sustainable CEB production.