Effect of aggregate morphology characteristics on the voidage of aggregate loose packing based on 3D discrete element method

Abstract

• The aggregate model with real morphology was generated by Clump method. • A 3D aggregate database considering real morphology was established. • The void spatial distribution of aggregate loose packing was studied. Reducing the voidage of aggregate loose packing can improve the workability of concrete, and aggregate morphology directly affects the voidage of aggregate loose packing. This paper combined 3D laser scanning and digital image processing (DIP) technology to perform statistical analysis on aggregate morphology characteristics such as sphericity, flatness, elongation and angularity index. A 3D aggregate database was built using the structured query language (SQL). On this basis, the discrete element model of loose packing was established by the gravity falling method (GFM), considering the natural morphology of aggregates; and the effect of aggregate morphology characteristics on the voidage and void spatial distribution of loose packing under different gradations was quantitatively studied. The results show that the voidage of aggregate loose packing decreases as aggregate sphericity increases and increases with the increase in angularity index. The effect of sphericity on the voidage of aggregate loose packing is about five times that of angularity index. In addition, the voidage in aggregate packing is arranged in Z-shape, and the larger the aggregate sphericity or, the smaller the angularity index, the more uniform the voids in the aggregate packing are distributed.