Evaluation of three Italian tuffs (Neapolitan Yellow Tuff, Tufo Romano and Tufo Etrusco) as compatible replacement stone for Römer tuff in Dutch built cultural heritage

Abstract

Rhenish tuffs from the volcanic Eifel region in Germany, in particular the so-called Römer tuff, are among the most prominent and voluminous natural stones in Dutch monuments. The Römer tuff has been used since Roman times, and was widely used again in Romanesque (and to a lesser extent Romano-Gothic and early Gothic) architecture. The limited (or non) availability of Römer tuff for restoration purposes is posing an increasing problem. Last decennia, the availability of Römer tuff was practically limited to blocks from the lower parts of the pyroclastic flows with abundant basalt (and other) xenoliths, giving the rock a different appearance from its traditional type; the different types of Römer tuff also demonstrate different physical and hygric properties. Given the wide use of tuff stone in Italian architecture, several Italian tuffs have been evaluated in search of a compatible replacement stone for Römer tuff. The replacement stones should approach the original as much as possible, that is, in terms of authentic appearance, physical characteristics and durability. The Italian tuffs evaluated include tuffs commercially denominated as Tufo Etrusco and Tufo Romano (from the central part of Italy) and a variety of Neapolitan Yellow Tuff (Naples region). Hygric behaviour, resistance to frost-thaw cycles, petrographic characteristics and mineralogy of Italian tuffs have been determined and compared with original Römer tuff. In all three cases, resistance to frost-thaw cycles is unfortunately shown to be considerably less than that of original Römer tuff. In addition, hygric expansion of the Neapolitan Yellow Tuff appeared to be considerably larger than that of original Römer tuff. Of the tuffs evaluated, the variety of Neapolitan Yellow Tuff is a good match with the original Römer tuff in terms of visual appearance. It has already been sparsely used in the Netherlands in minor amounts. However, the durability characteristics require additional evaluation.

The Value of Original Natural Stone in the Context of Architectural Heritage

“…In the same issue, Pereira et al provided a paper on serpentinites from Galicia, Spain, reporting the unacceptable characteristics of these rocks for construction purposes, in contrast to some other serpentinites from elsewhere. Three tuffs from Italy were described by [39] to validate their use as replacement in some historical building. Figueiredo et al [40] presented two Portuguese stones and Alloca et al described the Vitulano marbles, which are important for the preservation of cultural heritage of Southern Italy [41].…”

Characterization, performance and replacement stone compatibility of building stone in the 12th century tower of Dudzele (Belgium)

“…Also Römer tuff, a volcanoclastic rock, is recognized in small quantities. This stone is known to be widely used in Dutch Romanesque architecture (Nijland et al, 2010), but is far less common in northwestern Belgium.…”

Replacement stones for Lede stone in Belgian historical monuments

“…The proximity of the resources to the NW part of Belgium also limits the ecological footprint of transport, which fits in well with the recent quest for sustainability. Traditional examples are Saint-Pierre-Aigle and Saint-Maximin from the Calcaire Grossier (Dusar et al 2009), which are also used in The Netherlands (Nijland et al 2006;Quist 2011). However, the use of these rocks has never occurred consistently.…”

“…The compatibility of the original stone type with its replacement material has, therefore, been assessed by several researchers (e.g. Beck & Al-Mukhtar 2010;Nijland et al 2010;Graue et al 2011).…”