Experimental study for the consolidation of load-bearing limestone walls applied to the building of Wekalat (Caravan Sarai) Uda-Basha in the city of Cairo

نوع المستند : المقالة الأصلية

المؤلف

Faculty of Archaeology, Cairo University.

المستخلص

The research discusses the various steps of examination, analysis and consolidation of the limestone that was used in the construction of Islamic buildings in the city of Cairo, in the application of the Wekalat Uda-Pasha in Historic Cairo. Standing on the current status it has reached, to protect it from collapse and fall as a result of the severe neglect that it reached due to the lack of archaeological awareness. Fallen limestone Samples were taken from different places to know the chemical composition and to identify the most important damages that occurred to it, then evaluate and consolidate it for the best, which makes it stronger and bear the pressures and loads that fall on it and it's resistant to various damage factors.
X-ray diffraction was used, as well as the X-ray fluorescence device. A scanning electron microscope equipped with the EDX unit was also used to identify the chemical and mineral composition, as well as some impurities and salts in the limestone. The results of the analysis confirmed the presence of sodium chloride salt. The samples were examined and analyzed, which proved that the building material is limestone, and the consolidation stages were carried out on a number of limestone samples with special tools and materials for that. The stages of the experimental side were carried out on cubes of limestone in order to carry out some physical and mechanical properties. The limestone was cut into cubes with dimensions of 3 centimeters, then they were numbered in preparation for consolidating them with different consolidation materials according to four cubes of limestone with each of the different consolidation materials giving each stage a special code to facilitate dealing with it.
The process of preparing samples for consolidation was carried out in three stages. Nano-calcite and Nano-lime were used with Wacker OH and it's solvent (mineral turpentine), in concentrations of 5%, 7% with the polymer and the solvent. Some physical properties were studied after consolidation in order to know the effectiveness and resistance of the various consolidation materials that were applied, and to know their behavior and the extent of their impact, whether on the internal structure of the stone or on its external texture.  Where the following properties were determined: bulk density, natural water content, water absorption, and apparent porosity. Where the Nano-calcite material 7% with Wacker OH proved its effectiveness and recorded the highest bulk density, as well as the lowest natural water content and the lowest apparent porosity, as well as the lowest water absorption rate.
Some mechanical properties of limestone samples were determined after the various stages of consolidation, the most important of which is the compressive strength, as the Nano-calcite 7% with Wacker OH also proved its effectiveness and recorded the highest percentage. The stages of salt weathering were carried out using sodium chloride salt, which found in the analysis   at a concentration of 10% with water, then the compressive strength test was determined after salt weathering with the effectiveness of nanocalcite 7% with wacker OH.

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