Effects of lightweight particle content on the mechanical strength of cylindrical aggregates

Abstract

By using an extensive three-dimensional discrete element method, we numerically investigate the effects of lightweight particle content on the mechanical strength of the cylindrical aggregates, randomly composed of two different groups of primary particles: light (low stiffness) and heavy (high stiffness), and the stress contribution of the heavy-heavy, light-heavy, and light-light interactions on the mechanical behavior of such aggregates, subjected to the compression test by using a constant downward velocity. The interactions between primary particles are modeled by using the frictional-contact force law with a giving approximate analytical expression of capillary cohesion forces. We found that the lightweight particle content significantly affects the mechanical stress of aggregates and stress contribution obtained by different interaction types above, and the stress obtained by heavy-heavy interactions strongly dominates the mechanical strength of agglomerates. Remarkably, meanwhile, the stress obtained by the heavy-heavy contacts gradually decreases with increasing the lightweight particle content up to 20%, leading to the decrease of the mechanical strength, the stresses obtained by light-light and light-heavy contacts increase gradually. For higher lightweight particle contents, the results continuously show the same tendencies but with lower rates.