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Bouras Fawzi Al-Mukhtar Muzahim Tapsoba Nouffou Belayachi Naima Sabio Serge Beck Kévin Martin Mylène 《Geotechnical and Geological Engineering》2022,40(4):2033-2049
Geotechnical and Geological Engineering - An investigation performed on the interactions of silty soil treated with cement or lime demonstrates the strong relationship between microstructural... 相似文献
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Asaad Al-Omari Xavier Brunetaud Kevin Beck Muzahim Al-Mukhtar 《Environmental Earth Sciences》2014,71(9):3977-3989
This work consists in estimating the role of climatic conditions in the degradation of two French limestones, tuffeau and Richemont stone, used in the construction and the restoration of the Castle of Chambord, the largest castle in the Loire Valley, France. Meteorological data, air temperature, air relative humidity and rainfall were statistically analysed in combination with stone data from thermal–humidity sensors inserted into the walls. The climatic conditions of the surrounding area were described to assess their role in enhancing the degradation of the stones through three weathering processes: thermal stress, condensation and freezing–thawing. The damage risks due to the weathering processes were taken into account not only through the bulk effects on the stone surfaces, but also their effects were extended to investigate the damage that occurs within the porous structure of the stone. Field observations showed that the main patterns of degradation affecting the stones of the castle are biological colonization and stone detachment in the form of stone spalling and exfoliation. The results of the analysis show that there is no risk of damage to the stones due to thermal stress. Moreover, the two stones experience similar overall trends against freezing–thawing processes. Finally, this study clearly highlights the important role of condensation in the degradation of the stones of the castle. 相似文献
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Sarah Janvier-Badosa Kévin Beck Xavier Brunetaud Muzahim Al-Mukhtar 《Environmental Earth Sciences》2014,71(11):4751-4759
The main cause of degradation in tuffeau, a soft siliceous and clayey limestone extensively used in the construction of the castles of the Loire Valley in France, is scaling. The most damaging form of weathering is spalling. Over time, a plaque several centimetres in thickness gradually forms under the stone surface and eventually falls away, leaving the resulting new surface powdered. Hypotheses regarding the initiation and development of such degradation have not yet met scientific consensus. The objective of the present paper is to improve existing knowledge of scaling degradation by analysing in situ samples representing different stages of the same degradation process. The analysis of the stones at the Castle of Chambord, revealed the presence of gypsum (CaSO4·2H2O), mainly located in cracks parallel to the stone surface. This gypsum was then studied in terms of its crystal morphology and distribution with depth. For comparison purposes, another form of scaling identified at the Castle of Chambord but rarely studied, flaking, was also examined. A first attempt at explaining the origin and formation of the observed gypsum in both scaling processes was conducted by interacting and comparing the characterisation results with historical and environmental data. 相似文献
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Xavier Guillot Muzahim Al-Mukhtar Faiza Bergaya Jean-Marie Fleureau 《Comptes Rendus Geoscience》2002,334(2):105-109
Porosity measurements on a clay material, carried out through various microscopic techniques, show a significant difference with the total porosity macroscopically estimated. Analyses have allowed to assign this difference, whose importance is linked to the hydromechanical stresses sustained by the material, to microporous spaces lower than 2 nm and to closed pore volumes, not accessible by the used techniques. Besides, the role of the drying methods of samples, which do not allow the removal of a part of the water, is highlighted. Its elimination would lead to irreversible microtextural modifications, prejudicial to the understanding of the macroscopic behaviour of the material. To cite this article: X. Guillot et al., C. R. Geoscience 334 (2002) 105–109. 相似文献
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Accelerated weathering tests on two highly porous limestones 总被引：3，自引：0，他引：3
A major cause of weathering of building and historic monuments constructed using limestones is associated with the salt crystallization.
This may typically occur at the surface (due to efflorescence) or in subsurface layers while limestones are drying. Due to
this reason structural damage or material loss (granular disintegration, flaking, contour scaling) may occur. In this paper,
imbibition-drying cycles are carried out with pure water and solutions of NaCl with different concentrations to simulate the
weathering effect on two limestones with similar total porosity values. The imbibition kinetics of these limestones was significantly
influenced by the number of applied imbibition-drying cycles. In addition, imbibition kinetics was also dependent on the concentration
of salt solutions, the mineralogical composition as well as on the pore-size distribution of these two stones. The structural
and textural modifications that arise in the limestones due to the influence of imbibition characteristics of drying cycles
are qualitatively confirmed by scanning electronic microscope (SEM) and quantitatively with helium pycnometry measurements. 相似文献
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Formulation and characterization of an appropriate lime-based mortar for use with a porous limestone
Several studies have shown that the degradation of architectural monuments constructed using Tuffeau stones from Val de Loire region of France over a period of time are often related to use of mortars that are not compatible with the Tuffeau stones. For this reason, it is important to ensure physico-chemical compatibility between Tuffeau and the mortar. To alleviate differences in compatibility characteristics, a mortar is prepared from hydrated lime and aggregates obtained from the crushing of Tuffeau stone and used in this study. The key parameters that influence the strength and durability characteristics such as mechanical resistance, water transfer properties, and physico-chemical properties were identified and studied. Based on these studies, recommendations are offered for the preparation of a more compatible mortar that can be used in the construction and restoration of monuments using Tuffeau stone. 相似文献
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