Experimental study on spatial evolution of mode-I and mode-II fracture toughness of cemented paste backfill under external sulphate attack

ABSTRACT

External sulphate attack (ESA) interferes with spatial changes in fracture toughness of cemented paste backfill (CPB) and affects its mechanical stability. Large-scale curing column models are developed to investigate the spatial evolution of mode-I and mode-II fracture toughness (i.e. K_IC and K_IIC) under seepage- and diffusion-induced ESA. It has been found that the seepage-induced ESA leads to spatial changes in K_IC and K_IIC of CPB at advanced ages and higher extent of degradation of fracture toughness is measured at a deeper position in CPB. Comparatively, K_Ic can be used as a reliable quantity to estimate K_IIc under the diffusion-induced ESA.

KEYWORDS:

• Cemented paste backfill
• external sulphate attack
• fracture toughness
• heterogeneity

Acknowledgments

The authors would like to thank the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Lakehead University for their financial support.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Natural Sciences and Engineering Research Council of Canada under Grant NSERC RGPIN-2019-05078.