To address the issues of poor acid resistance of cement-stabilized soft soil and the high pollution

energy consumption

and cost associated with cement production

this study proposes using low-cost industrial solid wastes (ground granulated blast furnace slag (GGBFS) and fly ash (FA) in varying ratios) as precursors

with solid sodium hydroxide as the activator

to prepare geopolymer grout through a ‘one-step’ process for stabilizing soft soil. Subsequently

the geopolymer-stabilized soft soil samples were immersed in HNO and HSO solutions with different pH values (2

4

and 6). The acid resistance of the stabilized soil was evaluated at different erosion ages (30

60

120

and 240 days) using four indices: mass loss

unconfined compressive strength (UCS)

neutralization depth (ND)

and pH value. Furthermore

the changes in microstructure and hydration product composition of the samples under different acidic environments were investigated using scanning electron microscope-energy dispersive spectrometer (SEM-EDS) to reveal the degradation mechanisms. The test results indicate that compared to H2SO4 solution

HNO3 solution exerts a milder acid erosion effect on the stabilized soft soil. This is primarily because the Ca

K

and Na ions in the stabilized soil form nitrates in water

which can neutralize the erosion of ions

thereby mitigating the degradation of the soil’s properties. When the mass ratio of GGBFS to FA is 80:20

the acid erosion resistance of the geopolymer-stabilized soft soil reaches an optimal level. This suggests that the appropriate incorporation of FA can form a dense microstructure in the samples

effectively impeding the intrusion of H

and ions. The research findings can expand the application scope of low-cost industrial solid wastes and lay a theoretical foundation for the durability assessment of one-step geopolymer-stabilized soft soil.