16:15 〜 16:30
[MIS04-04] Limestone in heritage structures of Budapest; a comparative durability assessment of travertine and porous limestone
キーワード：weathering, limestone, mineralogy, surface strenght
The capital of Hungary, Budapest, has several monuments built of local stones forming parts of the UNESCO World Heritage site. The primary materials of these buildings are various types of limestone, including Miocene porous limestone and Pleistocene travertine. The first recorded use of these stones dates back to nearly two millennia with amphitheatre, aqueducts and urban buildings from the 1st century A.D. These monuments represent the architectural skills of the Roman Empire. The preferential stone type in these buildings is travertine. The travertine shows signs of deterioration, and now many of the historic stone elements are replaced by newer ones. The other common limestone type is the porous Miocene limestone, typically an oolitic grainstone and packstone. Some different varieties, such as shelly packstone and floatstone, also occur. The largest structure constructed almost exclusively from this stone is the Citadel, which has a length of 220 m and a wall height of 12 to 16 metres. This fortress located on the top of a small hill, although it is only 168 years old, is now in poor condition due to the intense weathering of the porous stone. The combined action of air pollution and freeze-thaw aggravated the condition of ashlars and walls of the monument. Weathering forms such as black crusts, white crusts, scaling, flaking and granular disintegration led to significant material loss. Travertine buildings from the same period are in better conditions with less pronounced decay patterns. The paper describes the current conditions of these monuments. It compares the deterioration process of travertine and porous limestone in an urban environment focusing on the differences in weathering forms, surface strength and mineralogical composition.