Weathering and consolidation trials on sandstones used in Irish Monuments.

Abstract

The objective of this study was to assess the efficiency of consolidant treatments in improving the durability of Irish sandstones, particularly sandstones used in national monuments at Cashel, Clonfert and Clonmacnoise. Although not located directly on the coast, these sites have been severely exposed to combinations of wind-driven rain, high levels of moisture from groundwater and salt decay. Samples of the sandstones were characterised and artificially weathered. The majority of salts were washed from the samples and they were then treated with alkoxysilane consolidant treatments. Consolidant treatments were modified by the addition of solvents and nanoparticles; the former to aid penetration in low porosity samples and reduce film thickness, the latter to increase the gel?s elastic modulus, improving cohesion and shrinkage resistance. Further weathering tests were also carried out in order to compare the durability of the treated and untreated samples. Surfacesubstrate interface stresses due to poor penetration of consolidant were observed. According to the results of this research, the alkoxysilane consolidants improved cohesion between constituents and the stone?s durability to both thermal and crystallisation stresses.