Carbon nanotube reinforced cementitious tailings composites: Links to mechanical and microstructural characteristics

The special hexagonal structure of carbon nanotubes (CNTs) leads to bending, exhibiting a spatial topology. Thus it has excellent electrical, mechanical and thermal stability and other properties. To explore the effect of CNTs on cementitious tailings backfill (CTB)'s strength behavior, two types of CNTs: hydroxylated (CNTCOOH); ordinary multi-walled (CNTPL) were used in this study. CNTs with six different concentrations of 0% (control), 0.05%, 0.10%, 0.15%, 0.20%, and 0.25% were added to prepare CTB specimens, respectively. CTB's strength and microstructure were thoroughly studied by UCS (unconfined compressive strength) tests and SEM (scanning electron microscopy) observations. The leading inferences revealed that: the bridging effect of CNTs inhibited significantly the expansion of the cracks occurred within CTB specimens, representing good integrity after failure. Both CNTPL and CNTCOOH improve the UCS performance of the tested composites. However, CNTPL provided the best boosting effect on the mechanical properties of CTB. Although CNTCOOH-reinforced fills are not as superior in UCS as CNTPL-reinforced ones, CNTCOOH shows better ductility performance than others. To sum up, this study's key end is that it is viable to use the fractal properties of microstructure for better estimating the strength development of CTB specimens reinforced with diverse CNTs.

Automated summary

This study investigates the effect of carbon nanotubes (CNTs) on the strength behavior of cementitious tailings backfill (CTB). The results show that CNTs significantly improve the strength and microstructure of CTB by inhibiting crack expansion and enhancing material integrity. Among them, ordinary multi-walled CNT (CNTPL) has the most significant impact on the mechanical properties of CTB. In conclusion, this study demonstrates that using the fractal properties of microstructure can better estimate the strength development of CTB specimens reinforced with different types of CNTs.