Effects of aggregate strength and mass fraction on mesoscopic fracture characteristics of cemented rockfill from gangue as recycled aggregate

The discrete element model considering media properties and interface differences was constructed for revealing the mesoscopic fracture characteristic of cemented rockfill in this study. The effects of aggregate strength and mass fraction on strength, deformation, energy and cracking of cemented rockfill were investigated. The results showed that the generally concerned two-element intergranular fracture between aggregates and cement matrix ITZ only plays a leading role in one fracture characteristic, but the failure induced by damaged aggregates is more severe than this fracture characteristic. The fracture characteristic transformation induced deterioration of cemented rockfill is catastrophic. The compressive strength of the specimen produced from 12.88 MPa gangue is nearly 30% worse than that of 32.77 MPa. And this fracture characteristic transformation is related to the aggregate mass fraction. The aggregate strength corresponding to the turning aggregate to cemented matrix strength ratio decreases from 52 MPa to 32 MPa with increasing the aggregate mass fraction from 42.7% to 57.7%. Therefore, the development of cemented rockfill requires more attention to the compatibility as char-acterized by the aggregates to cement matrix strength ratio and aggregate mass fraction. As the strength ratio increases, the recycled aggregates transform from defect clusters to load bearing phases in cemented rockfill.

Automated summary

In this study, a discrete element model considering media properties and interface differences was constructed to reveal the mesoscopic fracture characteristic of cemented rockfill. The effects of aggregate strength and mass fraction on strength, deformation, energy, and cracking of cemented rockfill were investigated. The results showed that the failure induced by damaged aggregates is more severe than the generally concerned two-element intergranular fracture. The development of cemented rockfill requires attention to the compatibility characterized by the aggregates to cement matrix strength ratio and aggregate mass fraction.