The dry dock in Dekheila is an archaeological and architectural study and an assessment of the current situation and requirements for restoration and maintenance

The research aims to study the archaeological dry dock located in the city of Dekheila in Alexandria, and its importance stems from the fact that it is a distinct and unconventional style in Islamic architecture, and the remaining models of it are rare. Muhammad Ali Pasha ordered the establishment of the dry dock in Dekheila in Alexandria in 1835 AD to build and repair ships within his strategic interest in strengthening the naval forces and increasing the fleet. The research dealt with the dry dock from an archaeological and architectural point of view, with a study of its current situation and the manifestations of damage and deterioration that it suffers from. An analytical study was carried out on the components and manifestations of damage to the building materials of the dry dock, where samples of stones, mortars and layers of paints were taken to study their mineral composition using polarizing microscope, scanning electronic microscope and X-ray diffraction method. The physical and mechanical properties of the limestones used in its construction were also studied to identify their condition, and the results of this study showed that the limestones used in construction are primary limestones that contain petroglyph-shaped fossils, The scanning electron microscope also showed the disintegration of the components of the stones and the exposure of some parts to dissolution and the presence of crystallized salts between the mineral components and the presence of gaps and separations. The results of the X-ray diffraction analysis showed that the limestones used in the construction of the dock consist mainly of calcite CaCO3, a small percentage of quartz SiO2 in addition to some iron oxides, and a small percentage of the minerals Dolomite Ca, Mg (CO3)2 and halite NaCl, It was also found that the mortar used in it is a mixture of lime and sand. As for the layers of paint, it was found that they consist of the minerals calcite and quartz. Both the mortar and the layers of paint contained halite (sodium chloride) as a result of exposure of the stones to sea water, which led to damage and deterioration. The results of the study of the properties of the physical and mechanical properties of the limestones used in the construction of the basin showed a decrease in the pressure-bearing strength of the stones with an increase in their water absorption and porosity. This is due to the various internal and external damage factors it is exposed to, which in turn led to many manifestations of damage. It became clear from the study the destructive effect of sea water and sand-laden winds on the damage and deterioration of dry dock building materials. The research concluded with recommendations for restoration, treatment and maintenance of dry dock damage and deterioration to preserve and protected it as a rare example in Egypt of this type of architecture.