TY - GEN A1 - Hünger, Klaus-Jürgen A1 - Danneberg, Matti A1 - Herold, Steven A1 - Acker, Jörg T1 - Stress conditions in quartzite and their quantification by Raman spectroscopy T2 - Proceedings of the 16th International Conference on Alkali-Aggregate Reaction in Concrete N2 - The silica solubility of aggregates is one of the most important components of the alkali-silica reaction. It is a surface-controlled process that always still requires more detailed studies to better understand the reaction mechanism. Since strained quartz releases more SiO2 into the pore solution, the properties of grains, crystals and their structure can should be directly quantified. In other work, various possibilities were tested for this purpose in order to obtain analyses of the surface and to correlate these with the mortar bar tests, for example. However, a quantifiable direct measurement of quartz crystal states with satisfactory results has not yet been performed. In this thesis polarization and reflected light microscopy in combination with Raman and confocal microscopy is used to obtain quantifiable data by direct measurement of the strained crystals. First measurements show new surprising signals besides the Raman main peak of the quartz. Such signals cannot be found on the whole sample, but only at places where strains are expected, e.g. at contact zones between different quartz crystals or cracks and sometimes inside of quartz grains too. Thus, a method may have been found to quantify the strained state of different quartz crystals in natural quartzite rocks. KW - ASR; quartzite; Raman microscopy; surface analysis Y1 - 2021 UR - https://opus4.kobv.de/opus4-UBICO/frontdoor/index/index/docId/27538 SN - 978-972-49-2315-4 SP - 185 EP - 192 PB - LNEC ER -