Nature-Based Stabilization of Traditional Rammed Earth Construction in Central Morocco: A Multi-criteria Assessment of Local Soils and Waste Sawdust Integration

In response to the Al Haouz earthquake (September 2023) in Morocco, this work investigates the optimization of rammed earth (RE) construction using local soils from the Rehamna region. Four soil types were characterized geotechnically, mineralogically, and chemically according to Moroccan seismic guidelines. Sawdust, a wood waste by-product, was incorporated at 0–2 wt.% to enhance mechanical and thermal performance. Results indicate that 1.5 wt.% sawdust provides optimal improvements, with a 35% rise in compressive strength (From 1.03 to 1.40 MPa), a 19% reduction in thermal conductivity (From 0.344 to 0.273 W/m·K), and enhanced acoustic performance (NRC 27.4%, STC 41.9). This study validates sawdust-stabilized rammed earth as a sustainable, thermally efficient, and seismically appropriate material for post-disaster rural construction.