Abstract:

In order to provide mix ratio design references and theoretical support for the promotion and application of geopolymer grouting materials in road trenchless grouting reinforcement and other projects， for slag-fly ash geopolymer grouting materials （SFGGM）， the influences of water-to-binder ratio， alkali equivalent， sodium silicate modulus and fly ash content on multiple key indicators such as fluidity， setting time， drying shrinkage rate and mechanical property were obtained through range analysis and analysis of variance by using four-factor and four-level orthogonal experiments. On this basis， a comprehensive weight analysis of multiple indicators was conducted with AHP-entropy method to select the optimal mix ratio scheme that takes into account workability， volume stability and mechanical property. The results show that the water-to-binder ratio has the most significant impact on fluidity. As the water-to-binder ratio increases， the fluidity of slurry improves significantly. The alkali equivalent is the dominant factor controlling the setting time and drying shrinkage rate. If alkali equivalent is too high， it will lead to shorten setting time and increased drying shrinkage rate. The fly ash content is a key factor affecting compressive strength and flexural strength. Excessive content leads to a decrease in compressive strength and flexural strength. Moderately increasing the alkali equivalent and sodium silicate modulus is conducive to promoting strength development. The main influencing factors of each performance index obtained from range analysis and analysis of variance are consistent. The optimal ratio for comprehensive performance is as follows： water-to-binder ratio 0.6， sodium silicate modulus 1.6， alkali equivalent 6%（mass fraction）， and fly ash content 0.4（the proportion of total mass of silicon and aluminum source ash）.

Key words: geopolymer grouting material, optimal mix ratio, orthogonal experiment, AHP-entropy method, range analysis, analysis of variance