6 research outputs found
UTJECAJ PETROGRAFSKIH OBILJEŽJA SILIKATNIH STIJENA NA KVALITETU AGREGATA
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.Petrografska obilježja ishodiÅ”ne stijene bitno utjeÄu na mehaniÄka svojstva drobljenih kamenih agregata. Glavni cilj ovog rada bio je utvrditi odnose izmeÄu petrografskih obilježja nekih vulkanskih i subvulkanskih (silikatnih) stijena i otpornosti prema drobljenju agregata dobivenih njihovih usitnjavanjem. Otpornost prema drobljenju ispitivana je metodom "Los Angeles". Tijekom ispitivanja agregat je izložen dinamiÄkim optereÄenjima na udar i habanje. Mineralni sastav i druga petrografska obilježja odreÄeni su petrografskim i elektronskim mikroskopom, te metodom rendgenske difrakcije na prahu vertikalnim rendgenskim goniometrom s CuKu (1,54 A) zraÄenjem. Kako bi se Å”to toÄnije ocijenila otpornost prema drobljenju ispitivanih agregata koriÅ”tena su Äetiri razliÄita pokazatelja: koeficijent Los Angeles (LA), koeficijent Los Angeles ostatka (LAr), indeks pregranulacije (Ir) i stupanj usitnjavanja (PR). Na temelju dobivenih rezultata kao najvažnija petrografska obilježja kamenih agregata u pogledu otpornosti prema drobljenju izdvojeni su: a- veliÄina kristala; b- oblik, prostorni raspored i meÄusobni odnos veliÄine kristala; i, posebice c - prisustvo mikropukotina u ishodiÅ”noj stijeni
ODREÄIVANJE OTPONOSTI KAMENIH AGREGATA NA PREGRANULACIJU
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 huhajuÄa optereÄenja. KoriÅ”tene su normirane i nenormirane metode ocjene pregranulacijc. Posebna pažnja posveÄena je poboljÅ”anju ocjene otpornosti prema pregranulaciji. PotvrÄene su pretpostavke da postoji ovisnost stupnja pregranulacije kamenih agregata o povrÅ”ini zrna agregata prije predrobljvanja. Ispitivanje je obavljeno normiranom metodom prema normativu HRN (LosAngeles). Za potpunu ocjenu agregata koriÅ”tene su i druge metode ispitivanja prema HRN-u. UtvrÄeno je da su dobivene vrijednosti posljedica strukturno-teksturnih i mineralnih znaÄajki, geneze, tektonike (postgenetskih naprezanja koja uzrokuju mikroraspucanost i kataklaziranje) i rekristalizacije. Elektronskim je mikroskopom utvrÄen utjecaj veliÄine, oblika i meÄusobne povezanosti kristala i mikroblokova na fiziÄka i mehaniÄka svojstva
Utjecaj teksturnih znaÄajki na ugradnju kamena
Prikazani su osnovni naÄini ugradnje kamena s obzirom na položaj njegovih strukturno-teksturnih obilježja (slojevitost, laminacija, Å”kriljavost, itd.) i objaÅ”njena je ovisnost trajnosti kamena o mjestu i naÄinu ugradnje u objekt. Uz to, date su i napomene u vezi s tom problematikom za neke od najpoznatijih hrvatskih varijeteta arhitektonskog kamena
OdreÄivanje otpornosti kamenih agregata na pregranulaciju
Kameni agregati dolomita, andezita i spilitiziranog dijabaza podvrgnuti su ispitivanju na udarno huhajuÄa optereÄenja. KoriÅ”tene su normirane i nenormirane metode ocjene pregranulacijc. Posebna pažnja posveÄena je poboljÅ”anju ocjene otpornosti prema pregranulaciji. PotvrÄene su pretpostavke da postoji ovisnost stupnja pregranulacije kamenih agregata o povrÅ”ini zrna agregata prije predrobljvanja. Ispitivanje je obavljeno normiranom metodom prema normativu HRN (LosAngeles). Za potpunu ocjenu agregata koriÅ”tene su i druge metode ispitivanja prema HRN-u. UtvrÄeno je da su dobivene vrijednosti posljedica strukturno-teksturnih i mineralnih znaÄajki, geneze, tektonike (postgenetskih naprezanja koja uzrokuju mikroraspucanost i kataklaziranje) i rekristalizacije. Elektronskim je mikroskopom utvrÄen utjecaj veliÄine, oblika i meÄusobne povezanosti kristala i mikroblokova na fiziÄka i mehaniÄka svojstva.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
INFLUENCE OF PETROGRAPHIC CHARACTERISTICS OF SILICATE ROCKS ON THE QUALITY OF AGGREGATES
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
ESTIMATION OF RESISTANCE OF STONE AGGREGATES TO RECRUSHING
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