Ionic soil stabilizers for mitigating drying shrinkage in solidified iron tailings: Enabling large-scale road base application

In the utilization of silty iron tailings as a pavement base material, it is crucial to access the drying shrinkage of the pavement base to mitigate the risk of reflective cracking in the surface course. This investigation aims to improve the crack resistance of the pavement base prepared with lime-fly ash stabilized iron tailings by adding an ionic soil stabilizer (ISS). Test results show that the incorporation of ISS effectively reduced the water evaporation of the stabilized iron tailing base material, leading to an increase in internal relative humidity. Besides, the ISS slightly elevated the total porosity of the stabilized iron tailings by hindering the pozzolanic reaction of fly ash, but can refine the microstructure given the increase of 5-10 nm pores and reduce the surface tension of pore solution. Therefore, the drying shrinkage of the lime-fly ash stabilized iron tailing base materials decreased significantly in the presence of ISS, given the refined pore structure, lower surface tension of pore solution, and greater internal relative humidity. In the utilization of iron tailings as pavement base, assessing drying shrinkage to mitigate reflective cracking risks is paramount. This study focuses on enhancing crack resistance in lime-fly ash stabilized iron tailing bases via ionic soil stabilizer (ISS). Tests results show that ISS significantly reduces water evaporation, boosting internal relative humidity. In addition, although slightly increasing total porosity by inhibiting fly ash pozzolanic reactions, ISS refines microstructure with 5-10 nm pore proliferation and decreases pore solution surface tension. Consequently, drying shrinkage of lime-fly ash stabilized iron tailing bases is markedly mitigated in the presence of ISS, attributable to pore structure refinement, lower surface tension, and elevated internal humidity. These findings offer insights into optimizing iron tailings application in pavement bases.