Abstract: In order to improve the utilization rate of solid wastes such as fly ash, slag, iron tailing sand and manufactured sand and prepare early strength and slightly expansive high-strength grouting material, the mechanical properties and microstructure of grouting materials were analyzed under the joint action of solid waste composite materials by mixing ordinary Portland cement and sulphoaluminate cement, designing the ternary composite system of quartz sand, iron tailing sand and manufactured and orthogonal test. The test results show that the optimal mass mix ratio of ordinary Portland cement and sulphoaluminate cement is 4 ∶1, the optimal mass mix ratio of quartz sand, iron tailings sand, limestone manufactured sand is 7 ∶1 ∶2, and the influence degree of four factors on strength of grouting materials from large to small in the orthogonal test is water binder ratio, fly ash content, binder sand ratio and slag content. Through range analysis, the optimal factor level combination is water binder ratio is 0.33, binder sand ratio is 1.0 ∶1.2, and the fly ash content and slag content are 6% and 10% (mass fraction), respectively. Through the analysis of XRD and SEM, it is found that the density of C-S-H gel will affect the strength of grouting material. The water binder ratio has an effect on the phase of ettringite, and ettringite and tricalcium aluminate hexahydrate can improve the early strength of specimens.

Key words: cement-based grouting material, ternary composite sand, orthogonal experiment, mixed cement, solid waste, hydration product