Title: Natural Aging of Different Moulding Products Used in Replacement of Stone Sculptures

Author(s): G. Fronteau, P. Bromblet, and F. Boutin

Publication: Symposium Paper

Volume: 212

Issue:

Appears on pages(s): 823-836

Keywords: durability; monument; mortars; moulding; natural aging; resin; weathering

DOI: 10.14359/12724

Date: 6/1/2003

Abstract:
For several years, in order to test the durability of 6 different moulding materials, samples were set on two prestigious French monuments (the cathedrals of Rheims and Rouen). These products are used for the replacement of stone sculptures in historical monuments. Even if their theoretical ageing behaviours have already been estimated by some compatibility tests or by artificial ageing in climatic room, the long-time natural ageing of these products have been too poorly characterised. Moulded samples were set in two exposures: 1/ in sheltered zones, protected from rain, where small slabs are submitted to the effects of the particulate pollution and 2/ in non-sheltered zones, where pseudo-sculptures are exposed to the effects of weathering agents: rain, sun and frost. Four mortar, two resin-based products and two reference limestones were tested. Durability was estimated by the following procedures: colorimetric changes, cracking measurements and visual observations. After 3 years of exposure, hand-made mortar shows numerous cracks (and su- perficial-cracking) whereas industrial mortars show better durability. Polyester-resin seems to have a very good durability potential or interesting behaviour regard to sooting. Investigations also reveal that moulding products have various durabilities which induce the development of different weathering-forms (erosion, cracking, powdering, darkening).