Faculty of Mining, Geology and Petroleum Engineering University of Zagreb
Abstract
The stone aggregates of dolomite, andesitic and spililized diabase were tested to estimate their response to abrasive-impact strain. Standardized and non-standardized estimation of recrushing action were utilized in the experiment. The focus of the study was to improve the estimation of resistance to the recrushing process. The assumption that there is a relationship between the degree of recrushing of the stone aggregates and the grain surface before recrushing was confirmed The investigation was performed by the use of the standardised method according to the HRN Standard (Los Angeles). For the complete evaluation of the aggregate several other methods in accordance to HRN were also applied. The values obtained are found to be the result of several factor which include structural, textural and mineral properties, as well as genesis, tectonics (postgenetic strain producing the micro-cleavage and cataclasis) and recrystallization. The influence of the size, shape together with the interrelationship of crystals and micro-blocks on the physical and mechanical properties were determined by electronic microscopy.Kameni agregati dolomita, andezita i spilitiziranog dijabaza podvrgnuti su ispitivanju na udarno huhajuća opterećenja. Korištene su normirane i nenormirane metode ocjene pregranulacijc. Posebna pažnja posvećena je poboljšanju ocjene otpornosti prema pregranulaciji. Potvrđene su pretpostavke da postoji ovisnost stupnja pregranulacije kamenih agregata o površini zrna agregata prije predrobljvanja. Ispitivanje je obavljeno normiranom metodom prema normativu HRN (LosAngeles). Za potpunu ocjenu agregata korištene su i druge metode ispitivanja prema HRN-u. Utvrđeno je da su dobivene vrijednosti posljedica strukturno-teksturnih i mineralnih značajki, geneze, tektonike (postgenetskih naprezanja koja uzrokuju mikroraspucanost i kataklaziranje) i rekristalizacije. Elektronskim je mikroskopom utvrđen utjecaj veličine, oblika i međusobne povezanosti kristala i mikroblokova na fizička i mehanička svojstva
