INFLUENCE OF PETROGRAPHIC CHARACTERISTICS OF SILICATE ROCKS ON THE QUALITY OF AGGREGATES
Journal Title: UNKNOWN - Year 2002, Vol 14, Issue 1
Abstract
The mechanical properties of chrushed rock aggregates are greatly influenced by the petrographic characteristics of parent rock. The main objective of this study was to determine the relation between the petrographic characteristics of some volcanic and subvolcanic (silicate) rocks from Croatia, and the chrushing resistance of aggregates produced by their comminution. The aggregate resistance to chrusing was tested by means of the Los Angeles abrasion test. During this testing, an aggregate is subjected to dynamic load by impact and abrasion. The petrographic characteristics were examined with the petrographic and scanning electron microscope and by X-ray powder diffraction with CuKa (1,54 A) radiation. In order to obtain the most correct evaluation of aggregates chrushing resistance, four different values had been used - the recrushing index (Ir), the reduction ratio (RR), the Los Angeles abrasion value (LA) and the Los Angeles abrasion value residue (LAr). On the basis of the obtained results, the following petrographic factors have been revealed as the most important ones for rock aggregates resistance to crushing: a - the size of crystals, b - the form, arrangement and dimensions ratio of crystals, and, especially c - the presence of microfractures in parent rock.
Authors and Affiliations
Mladen Fistrić Ivan Tomašić Maja Vrkljan
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