Sandstone

Effect of consolidation treatments on mechanical behaviour of sandstone, Ludovico-Marques, Marco, and Chastre Carlos , Construction and Building Materials, 11/15/, Volume 70, p.473-482, (2014) AbstractWebsite

Experimental research was carried out about into ethyl silicate applications on sandstone samples. Consolidation was assessed by drilling strength, impregnation depth and also monotonic and cyclic uniaxial compressive tests in order to evaluate the compressive mechanical behaviour of treated sandstone. The stress–strain compression diagrams showed a significant increase in the values of mechanical parameters after consolidation treatments. The difference in compressive strength values between monotonic and cyclic compression disappears after the consolidation treatments. An equation of consolidation effect was obtained from an analytical model by means of compressive behaviour assessed by stress–strain diagrams. These sandstone samples have values of porosity similar to the more weathered variety of sandstone found in facades of monuments in the village of Atouguia da Baleia, in the western region of Portugal. The most important degradation pattern found on sandstone building stones is alveolization caused by salt crystallization since the Middle Ages.

Effect of salt crystallization ageing on the compressive behavior of sandstone blocks in historical buildings, Ludovico-Marques, Marco, and Chastre Carlos , Engineering Failure Analysis, 12//, Volume 26, p.247-257, (2012) AbstractWebsite

Sandstone building stones are important in the building elements of Portuguese monuments, particularly in the western and southern regions. Alveolization due to salt crystallization was the most important degradation pattern found in the old sandstone façades of buildings in the village of Atouguia da Baleia. Because weathering progressively increases porosity in stones, experimental research was conducted on the most porous variety of sandstone, which is similar to the type of stones found in the façades of ancient buildings in that village. An automatic salt crystallization accelerated ageing chamber was developed. Monotonic and cyclic uniaxial compressive tests were carried out on samples after sodium chloride crystallization ageing tests had been performed, in order to assess the compressive mechanical behavior of sandstone during accelerated ageing. The results of stress–strain compression diagrams showed a clear decreasing trend in the values of mechanical parameters during the salt crystallization ageing progress. The difference in compressive strength values between monotonic and cyclic compression also decreases with as salt crystallization ageing progresses. A predictive equation that correlates the compressive strength of sandstones with salt crystallization ageing cycles is proposed.