MECHANICAL PROPERTIES AND MICROSTRUCTURE OF SALINE SOIL SOLIDIFIED BY ALKALI-ACTIVATED STEEL SLAG

The work aims to investigate the possibility of modifying and improving the mechanical properties of saline soil by incorporating alkali-activated steel slag (A-SS). The unconfined compressive strength of the solidified soil and the propagation velocity of the ultrasound in the solidified soil were tested. Moreover, the morphology of the microstructure was observed, and the chemical composition of the solidified soil was analysed. The results show that A-SS incorporation can improve the mechanical properties of saline soil, especially when the dosage of A-SS incorporation exceeds 15 %, the unconfined compressive strength of the soil can be significantly increased. The ultrasonic tests show that the ultrasound propagates faster in the solidified soil than in the original soil. The microstructure of the solidified soil with A-SS incorporation is much more compact than the original soil. Soil particles are combined by the formed gelatinous products, C-A-S-H and C-A-H, existing in a continuous form, which accounts for the noticeable increase in the unconfined compressive strength and the faster propagation velocity of the ultrasound in the specimens. Therefore, the solidification of saline soil by alkali-activated steel slag is feasible.