Evaluation of the Structure and Geometric Properties of Crushed Igneous Rock Aggregates

Abstract

The aim of this publication is to analyze the influence of rock mineral composition and rock geometric properties on the quality of crushed aggregates, from the perspective of selecting an adequate aggregate production technology. This research is based on samples of crushed aggregates from plants processing igneous rocks from four different igneous deposits. In the case of the geometric properties, shape and flakiness indexes were identified and subsequently analyzed along with particle size distribution. The performed tests allowed a conclusion that the shape of the particle is influenced by the mineral composition and size distribution. The grain size analysis demonstrated that flaky and non-cubical particles concentrate in the finest grain fractions, and the least variable shape index is observed for basalt aggregate. Some problems were also observed to exist in relation to the classification of grain shape. In the literature, the notions of regular and irregular grains seem to be used interchangeably with the notions of flaky and non-flaky grains. The performed tests show that flaky grains do not necessarily have to be non-cubical and vice versa. Therefore, this article proposes an approach in which the applied technique is precisely explained and the shape of grains is described with four notions: cubical, non-cubical, flaky, and non-flaky. The article also finally concludes that the next step in the research on selecting an optimal production technology of high-quality aggregates should be to analyze the selection of the fragmentation process while also characterizing the geometric properties of the aggregates.

Influence of Basalt Aggregate Crushing Technology on Its Geometrical Properties—Preliminary Studies

“…In the literature, the terms irregular and regular grains are very often used to refer to the non-flaky and flaky grains [ 15 ]. According to the corresponding author’s knowledge, it is not a correct interpretation.…”

“…From engineering geological aspects, the quality of rock aggregates mainly depends on the structure, texture and mineralogical composition of the host rock [ 9 , 12 , 13 , 14 , 15 ]. Moreover, the technical specifications of several aggregate-related engineering structures (i.e., concrete, paving mixtures and railway ballast material) emphasize and declare technical rock properties such as water susceptibility, freezing-thawing resistance, crushing and fragmentation resistance [ 16 , 17 , 18 ].…”

“…This crucial aggregate property has been investigated from many aspects. For instance, Räisänen and Mertamo [ 23 ], Hofer et al [ 24 ], Gawenda [ 2 , 25 ], Rajan and Singh [ 26 , 27 ], Köken [ 28 ], Köken and Lawal [ 29 ], Strzałkowski et al [ 15 ] and Gawenda et al [ 30 , 31 ] indicated that the shape properties of rock aggregates are dependent upon the rock manufacturing processes. In other words, different rock crushers have different impacts on rock aggregate flakiness, which ultimately affects the mechanical parameters.…”

“…Similarly, Rajan and Singh [ 26 ] observed that the aggregate obtained from two-stage crushing had higher grain irregularity compared to four-stage crushing. Strzałkowski et al [ 15 ] also indicated that flaky and non-cubical grains are concentrated in the finest grain fractions.…”

Analysis of the Aggregate Production Process with Different Geometric Properties in the Light Fraction Separator

“…Furthermore, the question of particle shape for various types of aggregates is commonly an important topic of many scientific works. Spheroidal and irregular particles and their properties as they affect applications and processing have been discussed in [34][35][36]. The elongation and flatness of particles were discussed in [37].…”