The effect of rock crusher and rock type on the aggregate shape

Abstract

Aggregate shape characteristics play an important role in the performance of the aggregate materials. The type of crusher and rock may play an important role in aggregate shape characteristics. The aim of this study is to investigate the effect of two types of crusher on the shape characteristics of different rock aggregate. The shape characteristics of aggregate in term of form, angularity and surface texture were evaluated using measured and visual methods based on international recommendations. Shape characteristics of aggregates were quantified by flatness ratio (F), elongation ratio (E), flat and elongated ratio (FE), shape factor (SF), aspect ratio (AR), sphericity (Sp), Rittenhouse’s sphericity (RS), Krumbein’s roundness (KR), number of fractured face (NFF), and texture-based BS (TBS). Also, the shape (S), angularity (A), and texture (T) factor in Fourier transform were used. Seven samples which have three rock types, i.e., limestone, marble, and tuff, were crushed by jaw crusher (JC) and horizontal shaft impact (HSI) crusher. Systematic statistical and graphical analyses were used to compare aggregate shape produced from different crushers and rocks. The results indicate that the rock type has important effects on the aggregate texture and crusher type has significant effects on the aggregate form characteristics. The rock aggregates produced with JC are mainly blade and disc form, and smoother surface with lower NFF. However, the effect of crusher type is different according to the rock type that has most affected in marble aggregates.