Rentgenska praškovna difrakcija betonov iz vojaških objektov ob Rapalski meji

Kranjc, Tadej (author), Meden, Anton (mentor)

Rentgenska praškovna difrakcija (XRD) je ključna nedestruktivna analitska metoda za določanje fazne sestave polikristaliničnih materialov, kot je beton. Metoda temelji na uklonu rentgenskih žarkov na kristalni strukturi snovi, kar omogoča identifikacijo prisotnih mineralnih faz. Namen diplomskega dela je bil s pomočjo XRD metode raziskati mineraloško sestavo betonskih vzorcev, odvzetih iz vojaških objektov ob nekdanji Rapalski meji, in tako oceniti njihovo ohranjenost in spremembo skozi čas. Poleg karakterizacije vzorcev in njihovih difraktogramov je bil cilj tudi osvojitev uporabe specializiranih računalniških programov za kvalitativno in kvantitativno analizo. Analiziranih je bilo trinajst različnih vzorcev betona. Po ustrezni pripravi so bili vzorci posneti z rentgenskim praškovnim difraktometrom. Pridobljene difraktograme sem najprej primerjal s programom X'Pert HighScore Plus. Sledila je kvalitativna fazna analiza s programom Crystallographica Search-Match (CSM) za identifikacijo prisotnih kristalnih faz. Za natančnejšo določitev sem uporabil kvantitativno analizo po Rietveldovi metodi s programom Topas. Ugotovljeno je bilo, da je kvantitativna analiza ključna, saj je v nekaterih primerih izboljšala ali popravila prvotne identifikacije iz kvalitativne analize. V analiziranih vzorcih so bile identificirane glavne mineralne komponente agregatov, kot sta dolomit in kalcit, ter različni produkti hidratacijskih reakcij cementa, kot sta larnit in portlandit. V nekaterih vzorcih sem identificiral dve dolomitni fazi z različnima osnovnima celicama, vendar verjetno ne gre za produkt dedolomitizacije, saj sta bila dva dolomita identificirana tudi v vzorcu čiste kamnine. Kompleksnost betonskih vzorcev zahteva natančen analitski pristop, pri čemer se je kombinacija uporabljenih programov izkazala za učinkovito. Rentgenska praškovna difrakcija je potrdila svojo uporabnost za karakterizacijo zgodovinskih betonov in razumevanje njihove dolgoročne obstojnosti.

• Language: Slovenian
• Keywords: rentgenska praškovna difrakcija, beton, Rapalska meja, kvalitativna analiza, kvantitativna analiza, mineralne faze
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2025
• PID: 20.500.12556/RUL-171768
• COBISS.SI-ID: 252412419
• Publication date in RUL: 02.09.2025

Secondary language

• Language: English
• Title: X-ray powder diffraction of concrete from military buildings along the Rapallo border

Abstract

X-ray powder diffraction (XRD) is a key non-destructive analytical method for determining the phase composition of polycrystalline materials, such as concrete. The method is based on the diffraction of X-rays by the crystal structure of substances, which enables the identification of the mineral phases present. The purpose of this diploma thesis was to investigate the mineralogical composition of concrete samples taken from military structures along the former Rapallo border using the XRD method, and thus to assess their preservation and changes over time. In addition to the characterization of the samples and their diffractograms, the goal was also to master the use of specialized computer programs for qualitative and quantitative analysis. Thirteen different concrete samples were analyzed. After appropriate preparation, the samples were recorded using an X-ray powder diffractometer. The obtained diffractograms were first compared using the X'Pert HighScore plus program. This was followed by qualitative phase analysis with the Crystallographica Search-Match (CSM) program for the identification of the crystalline phases present. For more precise determination, quantitative analysis using the Rietvheld methos was performed with the Topas program. It was found that quantitative analysis is crucial, as in some cases it improved or corrected the initial identification from the qualitative analysis. In the analyzed samples, the main mineral components of the aggregates, such as dolomite and calcite, and various products of cement hydration reactions, such as larnite and portlandite, were identified. I also identified two dolomite phases with a different unit cells were identified in certain samples but it was probably not a product of the dedolomitization reaction, as similar two phases were found in a pure stone. The complexity of concrete samples requires a precise analytical approach, and the combination of the programs used proved to be effective. X-ray powder diffraction confirmed its usefulness for the characterization of historical concretes and for understanding their long-term durability.

• Keywords: X-ray powder diffraction, concrete, Rapallo border, qualitative analysis, quantitative analysis, mineral phases