Effects of Carbon Nanotubes on Mechanical Strength, Damage Process, and Microstructure of Lithium Tailing Backfilling

In this study, common multiwalled and carboxylated carbon nanotubes (CNTs) were added to the cemented lithium tailings backfill (CLTB). The effects of CNTs on the mechanical properties, hydration products, damage process, and microstructure of CLTB specimens were studied by uniaxial compression (UCS), infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The experimental results show that the addition of CNTs effectively increased the compressive strength compared with the blank control group. When the concentration was 0.05-0.20%, the compressive strength was proportional to the content, the optimal addition amount was 0.2%, and the enhancement effect was 75% and 95.31%, respectively. The FT-IR results indicate that the addition of CNTs increased the total amount of the hydration product but did not affect its type. The hydration of the three-dimensional reciprocal penetration network formed by moderate amounts of CNTs has a positive effect on the mechanical strength of CLTB specimens.