Comparative mechanical, microstructural, durability performance and life cycle assessment of pectin and inulin versus xanthan gum in loam soil stabilization

Microbial xanthan gum (XG) is a well-known stabilizer for loam soil, however plant-derived biopolymers such as pectin and inulin may offer better performance due to their distinct stabilization mechanisms. This study therefore compares these plant-derived biopolymers with XG to evaluate their effects on the strength, durability, microstructure, and LCA of loam soil, using treated samples tested after 1, 7, 28, 56, and 90 days by UCS, ultrasonic pulse velocity, F-T cycles, and microstructural analyses. Compared with inulin and XG, 1% pectin after 28 days provided the highest compressive strength, increasing the strength of loam from 230 to 5102 kPa. Pectin also exhibited the best performance under F-T cycling. This improvement was associated with the formation of a dense hydrogel network that coated mineral surfaces and reduced pore spaces. Although pectin provided the greatest mechanical and durability enhancements, the comparative LCA showed that inulin achieved the highest overall environmental performance, with MPPI scores of 0.67, 0.60, and 0.50 for inulin, XG, and pectin, respectively, under scenario S2. These results indicate that pectin and inulin can improve the performance of loam soil compared with XG; however, inulin emerged as the best performing biopolymer when structural integrity and environmental sustainability were considered simultaneously.