STABILIZATION OF DELAMINATION IN ORTHOCERATITE LIMESTONE Gravestone 89 at Stampen cemetery, Gothenburg: Injection grouts field testing and implementation

Abstract

In Sweden, organic adhesives are often used to re-establish adhesion of delaminating Orthoceratite limestone. The injection of organic adhesives may alter the performance characteristics of the stone, with risk of further damage linked to environmental factors. Hydraulic lime-based grouts are likely to be physico-mechanically and chemically compatible with Orthoceratite limestone and might serve as an alternative. Objects and architectural surfaces made of Orthoceratite limestone are part of the cityscape. Delamination is a critical deterioration phenomenon of Orthoceratite limestone, which might lead to loss of original material. Therefore, conservation of Orthoceratite limestone is needed in order to prolong the existence of our built cultural heritage. Although adhesives are often used for stabilization of stone, few studies have been conducted on their impact on the material. Their impact should be examined and the possibility to replace them with a material that is physico-mechanically and chemically compatible with the original stone should be investigated. The aim of the research was to add to the investigation by evaluating different commercial hydraulic lime-based grouts and assess their suitability for stabilization through a case study of Gravestone 89, a red Orthoceratite limestone gravestone, at Stampen cemetery, in Gothenburg. The research includes a literature review of Swedish and international sources. The theory regarding the use of organic adhesives for stabilization of stone in Sweden was verified in the literature and through a survey. The results of the study suggests that the examined commercial hydraulic lime-based injection grouts were suitable for use in the case study, and that, therefore, they can be an alternative to organic adhesives in re-establishing adhesion in delaminated Orthoceratite limestone. Substitution of organic adhesives with a material that is compatible with the original stone reduces the risk of further damage caused by the intervention. Long-term monitoring is needed to confirm this for this particular stone in an outdoor environment.