Studie zkoumá vliv nestabilních K-silikátů a světlé slídy v kataklazovaném žulovém kamenivu na intenzitu alkali-silikátové reakce (ASR) v cementových betonech. Výsledky ukazují, že minerální složení zásadně ovlivňuje mikrochemii a morfologii ASR produktů.
Abstrakt
The main goal was to determine the reaction potential of alkali-reactive aggregates containing unstable and metastable K-silicates together with quartz (predominant SiO2 polymorph) for alkali-silica reactions (ASR) in cement concrete pavements. Current methods used to determine the expansion potential of aggregates do not solve these problems. The study of mineral paragenesis of cataclased granite by the SEM/EDX method shows that the differences in the microstructural and microchemical composition of ASR products in the cement matrix reflect the mineral variability of the rocks. The final products (crystals alkali-calcium aqueous silicates (NK)CSH), formed from alkali-silica gel (ASG), not only have different K2O contents, but analysis of internal and external ASG led to the finding that the K2O content is highest in cataclased granites with polymineral paragenesis (K-feldspar, light mica, quartz). The monomineral cataclased granite aggregate (crushed quartz only), its outer edge and air-voids have a significantly lower K content. The highest K2O contents and at the same time lower CaO content were identified in ASGs appearing in paragenesis with light mica, and crushed feldspars. Based on the results presented in this work, it can be concluded that the presence of transformed feldspars and light mica significantly affect both the microchemical composition of ASR products and their crystalline product morphology.
Dostupné na:
https://doi.org/10.1016/j.cscm.2024.e03521
Citace
Miroslava Gregerová, Jana Štulířová, Aleš Frýbort, Jiří Grošek, Impact of light mica on the intensity of the alkali-silica reactions in cement concrete pavements containing cataclased granite aggregates, Case Studies in Construction Materials, Volume 21, 2024, e03521, ISSN 2214-5095, https://doi.org/10.1016/j.cscm.2024.e03521. (https://www.sciencedirect.com/science/article/pii/S2214509524006727)