Particle size distribution of aggregate effects on mechanical and structural properties of cemented rockfill: Experiments and modeling

This study presents the particle size distribution of aggregate effects on the mechanical and structural properties of cemented rockfill. The uniaxial compression tests with acoustic emission (AE) monitoring, ultrasonic tests and scanning electron microscope (SEM) tests were carried out on the cemented rockfill, for which the aggregate particles satisfied the Talbot gradation theory. The particle flow model was constructed in the numerical software of PFC3D to reproduce the crack evolution and particle failure of cemented rockfill specimen. The AE characteristics, microstructures, numbers and distributions of initiated cracks and particle failure models of cemented rockfill under different particle size distributions of aggregates were discussed. The influence mechanism of the particle size distribution of aggregate on the strength, dilatancy and ultrasonic properties of cemented rockfill was analyzed. The results showed that the cemented rockfill with the overly fine or coarse particle size distribution of aggregate not only presented the more deteriorative microstructures, but also had the more early damaged areas with active AE signals and more initiated cracks during loading. However, the strength of cemented rockfill related to the crack distribution in the structure in addition to the number of initiated cracks. The concentration of cracks in the structure also caused the particle failure mode to present a certain dilatancy to further affect the loading capacity of the cemented rockfill. Among all the specimens, the cemented rockfill with Talbot index of 0.6 performed the relatively dense microstructures, superior structural properties and symmetric and uniform distribution of initiated cracks leading to optimize its strength, deformation and ultrasonic properties. (C) 2018 Elsevier Ltd. All rights reserved.