Performance and mechanism analysis of copper tailings modified cement-based geopolymer grouting materials
Copper tailings were chosen to prepare copper tailings modified cement-based geopolymer grouting materials in order to promote the green growth of geotechnical engineering and enhance the efficiency of resource exploitation of tailings.The effects of water-to-solid ratio,copper tailings doping,alkali activator doping and alkali activator modulus on the performance indicators and microscopic mechanisms of the modified slurry were investigated.The results show that adding tailings can improve the compressive strength of the modified slurry stone,and that adding alkali activator can improve the overall reaction degree of the slurry as well as reduce the water separation rate of the slurry.Taking into account the performance indicators,the optimal ratio of the modified slurry is selected as water-to-solid ratio 1.0,copper tailings doping 30%(mass fraction),alkali activator doping 4%,and alkali activator modulus 1.6.Compared with pure cement slurry,the optimum proportion viscosity of the modified slurry is reduced by 11.1%,the fluidity of the modified slurry is increased by 22.3%,the water separation rate of the modified slurry is reduced by 29.7%,and the 28 d compressive strength of the modified slurry stone is only reduced by 9.5%.The geopolymer reactions in the modified slurry result in the formation of three-dimensional network structures such as C-A-S-H gel and N-A-S-H gel,which have excellent performance.The findings of this study can provide high-performance and low-cost grouting materials for geotechnical engineering,as well as reference for resource exploitation of tailings and other solid waste materials.
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