Concrete is an important building material in roadway support，but there are often quality problems in roadway construction，such as honeycomb surface，cracks，holes and large area damage，which need to be repaired in order not to affect the normal production.Geopolymer concrete has the characteristics of fast setting time，high early strength，strong interface bonding ability，low permeability，high temperature resistance，frost resistance，corrosion resistance，excellent durability and low energy consumption，low pollution and low cost in the preparation process，and has the potential to be used as concrete repair materials.At present，there is no consensus on the proportion design of geopolymer concrete.The fly ash and slag were activated using sodium silicate and sodium hydroxide as alkalin-activator solution for the preparation of geopolymer mortar.The effects of different alkali-activator modulus （1.0，1.2，1.4） and content （10%，15%，20%） on the mechanical properties of mortar at different ages （3 d，7 d，28 d） were studied.The results show that the modulus and content of alkali-activator have a significant effect on the mechanical properties of geopolymers.Too large or too small alkali-activator modulus and content are not conducive to the strength development of geopolymer mortar.When the ratio of fly ash to slag is 1∶1，the modulus of water glass is 1.2，the content of alkali is 15%，the flexural and compressive strength of geopolymer mortar reaches the best value.The 28 d flexural strength is 7.6 MPa，the 28 d compressive strength is 72.3 MPa.In order to further explore the mechanical properties of geopolymer concrete with different mix ratios，the orthogonal experiment with three factors and three levels was designed to study the effects of different water-binder ratio （0.45，0.50，0.55），fly ash content （30%，50%，70%） and sand ratio （30%，35%，40%） on the workability and mechanical properties of geopolymer concrete at different ages （7 d，28 d）.Taking the compressive strength as the evaluation index，the results show that fly ash content has the most significant effect on compressive strength，followed by water-binder ratio，and sand ratio has almost no effect on strength development.The results of variance analysis of 7 d and 28 d show that the content of fly ash has a highly significant effect on the compressive strength of geopolymer concrete，the water-binder ratio has a significant effect on the compressive strength of geopolymer concrete，but the sand ratio has no significant effect on the compressive strength of geopolymer concrete.Considering the workability and mechanical properties of geopolymer concrete，combined with the results of microstructure analysis，geopolymer concrete with water-binder ratio of 0.50 and fly ash content of 50% is a promising rapid repair material.