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

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• 作者：Jeremie Berthonneau^a ; ^{berthonneau@cinam.univ-mrs.fr" class="auth_mail" title="E-mail the corresponding author} ; Philippe Bromblet^b ; Fabien Cherblanc^c ; Eric Ferrage^d ; Jean-Marc Vallet^b ; Olivier Grauby^a
• 关键词：Building limestones ; Spalling decay ; Clay minerals swelling ; Hydric dilation ; Hygric dilation X-ray diffraction ; Transmission electron microscopy ; Dilation kinetic
• 刊名：Journal of Cultural Heritage
• 出版年：2016
• 出版时间：January-February 2016
• 年：2016
• 卷：17
• 期：Complete
• 页码：53-60
• 全文大小：3671 K

文摘

Medieval 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 montmorillonite/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.