By studying the phenomena of limestone built from the White Monastery in Sohag Governorate damage where this study discusses the results of the analyzes and the study’s petrographic limestone, we can study and discuss what has been done to analyze X-ray diffraction and X-ray flourecence, and by scanning electron microscope in order to determine the cause of the damage and to study the properties of limestone to choose the most appropriate treatment methods especially the internal structure affected by the environmental conditions surrounding the private and increasing ground water levels along with the use of the most appropriate ways to buffer water to conserve the limestone of the environmental factors that damage it.
The famous White Monastery Archimandrite is located near Sohag city in Upper Egypt (
windows, walls have been built sloping towards inside, resembling the walls of Pharaonic temples and the system bearing walls [
The present work aims to study the deterioration phenomena in White monastery walls and blocks and to propose the suitable methods of restoration.
Historically stone masons have been worked with different stone materials as limestone, which was primarily used in building massive structures, to sand stones, clays, granite and marble which were more commonly found in statues and monuments. Since prehistoric times, and up till now, limestone is considered to be one of the widely common types of building stone, and in conservation practice as a replacement material for the reconstruction of monuments.
Calcite represents the main mineral constituent of the limestone, but the minor mineral constituents as well as structures and textures may result in a complicated weathering behaviour.
The ICOMOS-ISCS [
The White Monastery limestone bricks and walls have been affected by several weathering factors, all together controlled the type and extent of stone decay, [
1) Stone material fatigue: occurs as a result of temperature changes between day-night, as well as seasons, leading to volume changes expressed as expansion and shrinking, the continuous temperature change causes cracks and fractures on stones as a result of the material fatigue [
2) Internal disintegration: expressed as powdering of the stone behind the skin (surface crust), as a result of breaking down of the internal structure of the rock. This may be due to retention of fluids which are not allowed to escape by normal evaporation due to the impermeable nature of the skin. Some sets of cracks are noticed developed parallel to the exposed stone surface, and the internal structure is effectively shattered (
3) Efflorescence: soluble salts are considered to be the main cause of stone decomposition. Salts are usually cause stone damage in several ways. The most common is the growth of salt crystals in the stone pores, resulting in stresses that may overcome the stone’s tensile strength [
soluble salts dissolved in the fluids are concentrated, and on crystallization, the crystallized salts initiate the disintegration.. The soluble salts may, also crystallize on the stone surface forming unsightly deposits, known as “efflorescence”. The effect of salt deterioration is expressed on the limestone of the walls as shown in Figures 4-6.
4) Crust removal: the temperature change produces stresses resulted from the differential expansion, such stresses tend to cause delamination of the surface. When the wet stone surface warms by long exposure to the sun, as well as warm atmosphere, the surface expands and, contemporaneously, evaporation-precipitation processes takes place. Calcium sulphate crystals may be deposited in the fine cracks developed during the expansion phase. The repetition of these processes may produce an observed expansion and/or blistering of the crust (surface layers) (
5) Biodeterioration: the biologic activities of bacteria and algae, negatively, affect the stone mechanically and chemically, Mechanical damage is caused by penetration of the hyphae into the stone and by the expansion and contraction of the thallus (the vegetative part of the fungus) under changes of humidity. Chemical damage [
The nature of the limestone used in the construction of white monastery is studied and the nondestructive samples were collect to show its ability to deteriorate and to propose the suitable restoration procedures, Petrographic using Nikon polarizing microscope, scanning electron microscope using JEOL JSM5500LV, south valley University, Egypt, XRD analysis (using Philips diffractometer, Cu K radiation of 2 - 60 degrees, Department of Physics, Assiut University, Egypt). And chemical analysis methods were performed using (Axios advanced, sequential wd_XRF Spectrometer, PANalytical 2005) at the analysis and consulting unit, National Research Center in Cairo. The physical and mechanical properties of the limestone samples were also studied in lab of building materials properties, National Research Center in Cairo.
The studied limestones are Nummuliticbiomicrites and represented by a varying amount of fossils and fossil fragments embedded in a micritic matrix (
The study of the limestone samples with the scanning microscope show the presence of micropores and microcracks (
The resulted XRD charts show that the stones are composed mainly of calcite. Minor salts (Halite) and gypsum are observed with quartz (
The study of Chemical analysis of three limestone samples revealed CaO is the dominant oxide which ranges from 54.03% - 55.11% which reflects that the stones are mainly limestone with calcium carbonate content ranges from 96.11 to 98.37% (