Publication Date:
2010-04-01
Description:
The building stones of Tepla monastery (founded 1193) experienced a huge fire in 1677. Trachyte as a major rock type responded by changing colour from light beige to pink-red. Laboratory tests, during which the fresh unaltered stone from the original quarry was heated, proved the same reddened surface. Three varieties of local trachyte were examined: a greyish, naturally very fresh type (TA), a yellowish, slightly weathered and therefore iron hydroxide-bearing type (TB) and a trachyte typical with black manganese oxide dendrites and patches (TC). The changes of the physical properties and composition of these rocks were examined by ultrasonic velocity, thin section analysis, SEM observation and XRD tests. The experimental studies showed that Tepla trachyte is generally fire resistant up to 1000 {degrees}C.
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