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Description
The "yellow cobblestones" of Sofia are a historic ceramic pavement, with which about 6 hectares of the central streets of the Bulgarian capital were covered in the period 1907-1908. Today the whole reserved space is two times smaller and many of yet existing “yellow bricks” are broken or cracked.
This high quality ceramic clinker is characterized with unusually good degree of sintering coupled with an elevate crystallinity, which leads to extraordinary mechanical characteristics. The material was developed in Budapest in the end of 19th century and has been used as luxury pavement in various Hungarian cities and abroad. It was produced by a local Budapest’s marl with a specific chemical composition. After the exhaustion of the mine in the middle of 20th century this production was stopped.
The preliminary studies of various Bulgarian marls highlighted that somewhat similar raw materials exist also in Bulgaria, but the appropriated clays are characterized with lower MgO %. However, it can be noted that a certain amount of MgO in the composition is highly required because it influence positively on the sintering, phase composition and final properties. In fact, the attempts to use Bulgarian marls “as it is’’ to obtain similar high quality clinker was not very successful.
The aim of present work is to demonstrate the possibility to synthesize a material, very similar to the original "yellow cobblestones” of Sofia, by adding asbestos waste, containing a high percentage of MgO, to the used marl.
Acknowledgements: This research was financially supported by the project of KP-06-N67/13
Keywords ceramic clinker, marl, asbestos, sintering
| Scientific Sections | Revalorization of bio- and industrial waste |
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