Using biopolymer to stabilize silty soil-waste rock powder mixtures

This study presents an approach for potentially sustainable use of Xanthan gum (XG) biopolymer to improve the mixture of a low plastic silt (ML) and waste rock powder (WRP). A series of laboratory tests including standard compaction, unconfined compressive strength (UCS), fall cone (FCT), Atterberg’s limits, and California Bearing Ratio (CBR) tests were carried out on the specimens with 25% WRP and 0.5%, 1.0%, and 3.0% XG additions in the ML type soil. Testing results on the combined effect of WRP and XG exhibited a substantial increase in strength (increased up to 6 times), CBR (reached 65% at 56 days), and liquid limit values (increased to 50%) of the samples. Eventually, the results proved the use of both WRP and XG together in the ML type soil as an alternative sustainable technique to improve it under varying conditions. Moreover, the application of a tree-based regression model proved highly effective in predicting the shear strength of the samples. The model demonstrated exceptional predictive capability, achieving a coefficient of determination (R2) of 0.982 by the selected input parameters.