Decay of Rhenish Tuff in Dutch monuments. Part 2 : Laboratory experiments as a basis for the choice of restoration stone
article
Rhenish tuffs (Eifel, Getmany), have been used as building material in the Netherlands since Roman times. They were the most important natural building stone in the Netherlands in early medieval times. In addition, tuff was used as raw material for production of trass, that served as a pozzolanic addition for mortars. Rhenish tuffs, notably Römer, Weiberner and Ettringer, show remarkable differences in decay. Ettringer tuff applied during late 19'r' - early 20'h century restorations often shows severe deterioration, whereas, for example, most 14'h century Römer in rampant arches on top of St. John's cathedral, 's Hertogenbosch, resisted weathering reasonably well, as do sculptures out of the more fine-grained Weiberner tuff on top of these. In order to obtain a better understanding of the processes underlying the decay of these tuffs and the compositional factors controlling them, a research project was started that includes both on site investigations of major monumental buildings in the Netherlands (partly) built with tuff and laboratory reseatch. Fresh quarry samples of Römer, Ettringer and Weiberner tuff were used for selected physical characterization and testing, including a.o. hydric dilation, drying behaviour and frost resistance. One type of Römer showed a remarkably high resistance against frost. The results of the laboratory experiments on quarry samples are reported.
The experiments provide a sound basis for the choice of restoration stone.
The experiments provide a sound basis for the choice of restoration stone.
Topics
TNO Identifier
330673
Source
Heron, 48(3), pp. 167-177.
Pages
167-177