Multi-performance assessment of gum Arabic-stabilized compressed earth blocks

The construction industry is responsible for about 37% of global greenhouse gas emissions; therefore, there is a need for eco-friendly and sustainable construction materials. In this study, gum Arabic (GA), a natural, bio-based, and environmentally friendly polymer, is used as a stabilizing agent for compressed earth blocks (CEBs) made from calcareous soils extracted locally in the arid Drâa-Tafilalet region in Morocco. A multi-scale approach combining X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscope equipped with energy-dispersive X-ray spectrometry (SEM-EDX) was used to investigate the physico-chemical stabilization mechanisms. Microstructural analyses suggested the presence of physicochemical interactions between gum Arabic and the soil matrix that may contribute to the enhanced performance of the stabilized blocks. Parametric assessment in the GA range of concentrations from 0 to 5 wt% indicated the most favorable concentration of 4 wt%, Significant improvements in mechanical strength and water durability were achieved through gum Arabic stabilization. Small increase in density (+1.07%) to reduce porosity of CEBs (from 35% to 25%) caused an increase in thermal conductivity from 0.72 to 0.96 W/m·K, reflecting the densification of the material. This result illustrates the trade-off between enhanced mechanical and durability performance and a partial reduction in intrinsic insulation capacity. There is a strong correlation between densification and mechanical/thermal properties, thus indicating that GA acts as an efficient physical stabilizer without changing mineralogy of the soil. Unlike previous studies limited to macroscopic performance evaluation, this work provides a multi-scale physicochemical interpretation of gum Arabic stabilization mechanisms and establishes a direct link between microstructural interactions and multi-performance optimization of CEBs. However, the study remains limited to laboratory-scale investigations, and long-term field validation under real environmental conditions is required.