In order to address the issues about significantthermal disruption and carbon emissions associated with the use of cement forsolidifying frozen soil

calcium carbide slag was used as an alkali activatorto activate metakaolin based geopolymer for soil solidification. In thisresearch

the impacts of metakaolin and calcium carbide slag contents

curingtemperature and curing age on the compressive strength of the solidified soilwere investigated. Geopolymer solidified soil and cement solidified soil werecompared in parallel. The curing mechanism was studied by X-ray diffraction andelectron microscope scanning. Test results indicate that there is an optimalcontent of metakaolin and calcium carbide slag. When the content is lower thanthe optimal content

it plays an active role. On the contrary

it will have anegative effect. The optimal content of metakaolin and calcium carbide slag is10% and 6%

respectively. The compressive strength of the optimal contentsample cured at 20 ℃

–2 ℃ and –10 ℃ for 28 days is 3.783 MPa

1.164 MPa and 0.901 MPa

respectively. The main products of metakaolin basedgeopolymer activated by calcium carbide slag are amorphous hydrated calciumsilicate and hydrated calcium aluminate gel

which contribute to theimprovement of compressive strength of solidified soil. The compressivestrength of geopolymer solidified soil cured at –2 ℃ and –10 ℃for 28 days is 69% and 76%lower than that cured at 20 ℃

respectively. Due to theexpansion of the pores in the frozen state which is related to the ice crystal

the growth of cracks is promoted

the efficiency of geological polymerizationreaction is reduced and the amount of polymerization products is reduced.Compressive strength of the samples increases with the increase of curing age

because of the more silicon-aluminum grid structures produced by the geologicalpolymerization reaction

the lower the porosity of the solidified soil and theinternal structure of the soil is intertwined to form a denser structure. Thegeopolymerization reaction is less affected by low temperature. Compressivestrength of geopolymer solidified soil cured at 20 ℃

–2 ℃ and –10 ℃ for 28 days is 1.07

1.13 and 1.19 times that ofcement solidified soil

respectively. The research results lay a theoreticalfoundation for the application of geopolymer in subgrade soil reinforcement infrozen soil area.