Microscopic study of weathering of white Flemish stone from the monumental Church of Our Lady in Breda, The Netherlands

Microscopic study of weathering of white Flemish stone from the monumental Church of Our Lady in Breda, The Netherlands

TNO Bouw
Larbi, J.A.
van Hees, R.P.J.
Naldini, S.

2003

This paper deals with the use of an integrated microscopic method to assist in the investigation of the causes and the extent of decay of the stones and ornaments in the gothic Clurch of Out Lady in Breda, The Netherlands. The purpose of the study was to determine whether conservation measures were necessary. As part of the investigation 8 fluorescent thin sections were prepared from cores removed from the Flemish sandy limestone, used to build parts of the church and 4 from cores of an oolitic limestone, used for some of the architectonic ornaments and examined by means of fluorescent microscopy. The results showed that the processes and extent of decay vary for the two types of stone, although the causes of decay were similar. In the case of the sandy limestone, the decay processes, mainly conversion of calcite to gypsum and the formation of black crusts, were found to be largely restricted to the fine-grained calcite matrix. With regard to the oolitic limestone, the processes of decay were found not only to be confined to the microcrystalline calcite matrix, but also to the calciticoolites. In both cases, however, the occurrence, distribution and interconnectivity of cracks and micropores seemed to play an important role in the decay processes. In general, the stones that had always been exposed to outdoor weather were found to be more severely decayed than those in sheltered areas.

Natural stone
White Flemish stone
Gobertange
Lede
Conservation
Microscopic investigation
Buildings and Infrastructure
Built Environment

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330676

Heron, 48 (48), 207-219

Special issue verschenen in mei 2004

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