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Vpliv okolja na historične materiale z mineralnim vezivom : doktorska disertacija
Štukovnik, Petra (Avtor), Bokan-Bosiljkov, Violeta (Mentor) Več o mentorju... Povezava se odpre v novem oknu, Mirtič, Breda (Komentor), Mikoš, Matjaž (Član komisije za zagovor), Žarnić, Roko (Član komisije za zagovor), Marinšek, Marjan (Član komisije za zagovor), Zupan, Klementina (Član komisije za zagovor)

URLURL - Predstavitvena datoteka, za dostop obiščite http://drugg.fgg.uni-lj.si/5131/ Novo okno
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Izvleček
Na propadanje historičnih materialov z mineralnim vezivom v objektih stavbne dediščine lahko vpliva več različnih dejavnikov, ki so pogosto posledica sprememb v okolju, kjer se objekti nahajajo. Z namenom analize poškodb na arhitekturnih površinah in vzrokov za njihov nastanek smo na treh objektih stavbne dediščine, ki so v treh različnih klimatskih conah, opravili vizualno analizo in neporušne preiskave z mikroskopskim sistemom HIROX 3D. Na vseh analiziranih objektih smo odkrili podobne vzroke za ugotovljene poškodbe arhitekturnih površin (biodegradacija, razvoj soli, vlaga itd.), ne glede na klimatsko cono. Ugotovili smo tudi, da z mikroskopskim sistemom HIROX 3D lahko na objektu izvajamo monitoring delovanja in napredovanja površinskih razpok ter razpoke analiziramo, spremljamo pa lahko tudi kristalizacijo in raztapljanje soli na površini. Na vzorcih materialov z mineralnim vezivom, odvzetih z objektov (kjer je bilo to mogoče), smo v laboratoriju opravili petrografske preiskave z optičnim mikroskopom ter RTG in TGA analizo, z namenom karakterizacije historičnih malt in določitve vzrokov za poškodbe. Na vzorcih malt za zidanje iz palače Kolizej so bili opaženi reakcijski obroči, ki so pritegnili našo pozornost. V nadaljevanju doktorske disertacije smo pripravili replike analiziranih historičnih sklopov in materialov, za pospešene teste staranja. Za namen študija vpliva kristalizacije in raztapljanja soli na sklopu zid-omet smo razvili pospešen test, ki omogoča kontinuirano spremljanje oblikovanja in napredovanja poškodb z mikroskopskim sistemom HIROX 3D. Za namen študija reakcije med mineralnim vezivom in dolomitnim agregatom, opažene na maltah iz palače Kolizej, smo pripravili vzorce iz šestih različnih maltnih mešanic. Kot agregat smo uporabili apnenec ali dolomit, kot vezivo pa apneno testo, apneno testo z dodatkom tufa in čisti portlandski cement. Vzorce smo izpostavili različnim pogojem staranja (raztopini deionizirane H2O ali 1M NaOH ter temperaturi 20 °C ali 60 °C). V obdobju enega leta so na vzorcih sočasno potekale mehanske preiskave ter meritve modula elastičnosti, mase in dolžine vzorcev, ter preiskave z optičnim in elektronskim mikroskopom (SEM). Rezultati opravljenih preiskav so pokazali, da alkalno karbonatna reakcija (ACR) poteče med izbranim dolomitnim agregatom in vezivom ter vpliva na spremembe v mikrostrukturi malt in s tem tudi na spremembe mehanskih lastnosti. ACR se kaže kot proces dedolomitizacije, ki v preiskovanih maltah poteka v različnih stopnjah. Najnižja stopnja je proces raztapljanja po mejah med dolomitnimi kristali, to je selektivna dedolomitizacija. Sledi oblikovanje reakcijskega obroča. Pod optičnim mikroskopom se obroč vidi kot sprememba barve sparitnih kristalov iz bele v rjavo, pod SEM pa kot značilna mirmekitska tekstura. Skozi proces napredovanja ACR se oblikujeta tudi »Ca halo«, na meji med spremenjenim agregatnim zrnom in vezivom, ter »nova faza«, na robu spremenjenih delov dolomitnih zrn. ACR poteče ne glede na uporabljeno vezivo, so pa dinamika reakcije ter oblikovanje »Ca haloja« in » novih faz« odvisni od vrste uporabljenega veziva. Difuzija ionov dokazuje, da je sistem dinamičen in se s časom spreminja. Na napredovanje ACR vplivata tudi temperatura in izbrana vodna raztopina.

Jezik:Slovenski jezik
Ključne besede:gradbeništvo, disertacije, propadanje historičnih malt, 3D mikroskopski sistem HIROX, in-situ preiskave, laboratorijske preiskave, pospešeni testi staranja, alkalno karbonatna reakcija, mineraloške spremembe, spremembe mehanskih lastnosti
Vrsta gradiva:Doktorsko delo/naloga (mb31)
Tipologija:2.08 - Doktorska disertacija
Organizacija:FGG - Fakulteta za gradbeništvo in geodezijo
Leto izida:2015
Založnik:[P. Štukovnik]
Št. strani:XXXIV, 108 str., 11 str. pril.
Kraj:Ljubljana
UDK:504:691.53(043.3)
COBISS.SI-ID:7057761 Povezava se odpre v novem oknu
Število ogledov:545
Število prenosov:153
Metapodatki:XML RDF-CHPDL DC-XML DC-RDF
 
Skupna ocena:(0 glasov)
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Sekundarni jezik

Jezik:Angleški jezik
Naslov:Influence of environment on historical materials with mineral binder
Izvleček:
Deterioration of historical materials with mineral binders in buildings of architectural heritage can be influenced by several different factors, which are often the result of changes in the environment where the buildings are located. In order to analyse the damages of these materials and the causes for their occurrence, three buildings of architectural heritage located in three different climatic zones were subjected to visual analysis and non-destructive testing using 3D microscopic system HIROX. In all the analysed buildings we found similar causes of the observed damages of architectural surfaces (biodegradation, salt crystallisation, moisture, etc.), regardless of the climatic zone. We also found that with the 3D microscopic system HIROX we can monitor opening/closing and progress of surface cracks, carry out analyses of the cracks, and also monitor the crystallization and dissolution of the surface salts, all these in-situ. On the samples of materials with mineral binder taken from the buildings we performed (where possible) petrographic analyses with an optical microscope and X-ray and TGA analysis in order to characterize historical mortars and determine the causes of damages. Reaction rims were observed on samples of masonry mortars from the Kolizej palace and they attracted our attention. In continuation of the doctoral dissertation we prepared replicas of analysed historical render-masonry-plaster composites and mortars for accelerated aging tests. To study the impact of crystallization and dissolution of salts on the render-masonry-plaster composites we developed accelerated test that allows continuous monitoring of the development and progression of damages with the 3D microscopic system HIROX. To study the reaction between mineral binder and dolomite aggregate grains observed in masonry mortar from the Kolizej palace, samples were prepared from six different mortars. As an aggregate we used inert limestone or selected dolomite grains, and as binder lime putty, lime putty with tuff or pure Portland cement was applied. Samples were exposed to different accelerated ageing conditions (a solution of deionised H2O or 1 M NaOH, and a temperature of 20 °C or 60 °C). On the samples mechanical tests and measurements of the modulus of elasticity, change in weight and length of the samples, as well as optical and electron microscopy (SEM) analyses were simultaneously carried out in prescribed time intervals up to one year. The results of the tests show that the alkaline carbonate reaction (ACR) occurs between the used dolomite aggregate and binder, and its progress influences changes of the mortars’ microstructure and thereby also changes of mechanical properties. ACR is manifested as a dedolomitisation process, which takes place in investigated mortars in different stages. The lowest level is dissolving process along the boundaries between dolomite crystals, called selective dedolomitisation. In the next stage reaction rims are formed. Under an optical microscope, the rims can be seen as a change in colour of sparite crystals from white to brown and under the SEM as a typical myrmekitic texture. Through the progress of the ACR, secondary calcite ("Ca halo") is formed in the binder, close to the modified parts of dolomite grains, and a "new phase" on the edge of the modified parts of dolomite grains. ACR occurs and progresses regardless of the binder type, but the dynamics of reactions and the formation of "Ca halo" and "new phase" depend on the type of binder. Diffusion of ions shows that the system is dynamic and changes with time. The temperature and selected aqueous solution influence the ACR progression.

Ključne besede:civil engineering, thesis, degradation of historical mortars, 3D microscopic system HIROX, on-site tests, laboratory tests, accelerated aging tests, alkaline carbonate reaction, mineralogical changes, mechanical changes

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