The spalling decay of building bioclastic limestones of Provence (South East of France): From clay minerals swelling to hydric dilation

Abstract

International audienceMedieval historical monuments of the Provence region (South East of France) were erected with bioclastic limestones and display different sensitivities to spalling decay. The present study aims at understanding the physical processes at play as well as the internal properties governing its intensity. Limestones of contrasting sensitivity to spalling were compared to a reference type, unaffected by this decay, by means of petrography, petrophysic, mineralogy, and hydromechanics. The obtained results highlighted that the various sensitivities can be explained by the deformation recorded during water content variation (hydric dilation). A clay fraction was systematically detected within the mineralogical composition except for the reference material, and some swelling layers were identified in ontmorillonite/glauconite mixed layer minerals. A specific quantification procedure based on the combination of transmission electron microscopy coupled to an energy-dispersive X-ray spectrometer (TEM–EDX) and profile modeling of X-ray diffraction patterns was applied. A strong relationship between swelling layer content and hydric dilation of limestones was evidenced and corroborated the spalling sensitivity. Further interpretation of results showed that swelling layers localization within the texture significantly influence hydric dilation kinetics. Eventually, a mechanical softening was measured after water saturation. This behavior seems unrelated to the clay mineral content and its relative influence on spalling should be examined

Influence of cyclic wetting‐drying on the mechanical strength characteristics of coal samples: A laboratory‐scale study

“…Under cyclic wetting‐drying, the clay minerals have a high swelling‐shrinking capacity . Under frequent water adsorption and water loss, these minerals could induce microscale destruction of a coal specimens’ structure.…”

Influence of Water Content on the Mechanical Behaviour of Limestone: Role of the Clay Minerals Content

“…1 highlighting the wide variety of samples under investigation. Antique and modern Barutel stones show uniform pore size distributions while Estaillades stone exhibits a perfect bimodal pore size distribution (Berthonneau et al, 2015).…”

“…A particular stone deterioration pattern is called "spalling" or "contour scaling" (Vergès-Belmin, 2008), it corresponds to the progressive loss of plates from surfaces exposed to rain and/or runoff whatever their position in the building. The plane of detachment is located near the stone surface and develops perpendicularly to the bedding so that it cannot result from mechanical weaknesses linked to the sedimentary origin of limestones (Berthonneau et al, 2014(Berthonneau et al, , 2015.…”

“…Even with a small content, the clayey phase makes them highly susceptible to water content variation and may govern the hydro-mechanical behaviour. For instance, hydric dilation behaviour is directly related to the amount of swelling clay of various natural stones (Colas et al, 2011;Berthonneau et al, 2015). Under cyclic conditions of wetting and drying, swelling and shrinkage phenomena can have a major role in the deterioration processes (Jiménez-González et al, 2008;Ruedrich et al, 2011;Berthonneau et al, 2014).…”

The Impact of Hydric Swelling on the Mechanical Behavior of Egyptian Helwan Limestone

“…and the variation of the environmental conditions, among others. There are several references to the decay of limestones containing clays [6][7][8][9].…”