مطالعه و بررسی ذخایر رسی دراطراف منطقه چغازنبیل در راستای تهیه خشت مرمتی بهینه

برای ساخت مجموعه بناهای محوطه تاریخی چغازنبیل، بزرگترین اثر معماری شناخته شده از تمدن ایلام میانه در جنوب غربی ایران (استان خوزستان) مربوط به قرن 13 ق. م، امتیازات مساعد محیطی کاملاً به خدمت گرفته شده‌اند، در سواحل رودی که مقدار آب آن نا محدود نشان می‌دهد چوب برای سوزاندن جهت مصارف مختلف ( بویژه کوره‌های آجر پزی) و خاک مناسبی برای تولید خشت و آجر و ملات در اختیار بوده است بگونه‌ای که امروزه نیز کم و بیش چنین می‌باشد. مشخصاً در محوطه تاریخی چغازنبیل بیشترین حجم مصرف مصالح را خشت تشکیل داده است که عنصر اصلی در برپایی سازه‌های معماری به استثنای مخزن آب و مقابر زیر زمینی می‌باشد. با آنکه سطح عمده خشت‌های تاریخی چغازنبیل با اندودکاهگل و یا دیواره‌های خشتی مرمتی، درمرمت‌های گذشته پوشیده شده است اما بر اثر گذشت زمان وشسته شدن توسط آب باران آسیب دیده‌اند.در نتیجه این آسیب دیدگی قسمت‌های زیادی از بنا تخریب گردیده و بخش‌های وسیع‌تری در شرف نابودی قرار دارند که باید مرمت و حفاظت شوند. این کار مستلزم ساخت خشت‌های جدیدی است که حتی‌المقدور علاوه بر دارا بودن کیفیت لازم و ویژگی‌های کلی خشت‌های تاریخی، برخی از خواص آنها نیز با اجرای بهترین شرایط ساخت و عمل آوری، اصلاح گردیده باشد. این تحقیق با رویکرد کاربردی به دنبال شناخت ذخایر رسی مناسب برای تهیه خشت مرمتی بهینه در اطراف محوطه چغازنبیل است و می‌کوشد بر پایه روش‌های کمی و کیفی (فیزیکی، شیمیایی) پاسخگوی سوال اصلی یعنی چیستی عوامل موثر در انتخاب خاک مناسب برای تهیه خشت مرمتی بهینه باشد.در این راستا ذخایر سازندی اطراف محوطه جغازنبیل که درگذشته بررسی شده بودند مورد مطالعه و بررسی و ذخایر آبرفتی مورد آزمایش (xrd،xrf، دانه‌بندی، هیدرومتری و حدود آتربرگ) قرارگرفتند و مطلوب ‌ترین ذخایر (g3 و r2) برای تهیه خشت مرمتی انتخاب شدند.

study of clay resources in chogazanbil area for prepared optimize restoration mud brickes

The largest known architectural work of Ilam civilization is the temple of Choghazanbil from Medieval period, in Southwestern Iran (Khuzestan Province), dated to the 13st century BC. The temple has been made by terrestrial soil that has been taken, along riverbanks whose water content is unlimited, indicating wood for directional burning various uses, especially brick firing (and suitable soil for the production of bricks and mortar).That was done however more or less the same as today. The largest volume consumption of materials in Choghazanbil was based on clay that is a major element in the construction of architectural structures. The major architectural elements of historic site of Choghazenbil were bricks and adobe that have been covered in past marbles, but have become dull as time goes by. This research undertake for identifying appropriate clay reserves for optimal restoration purposes of the monuments. The material has been studied quantitatively and qualitatively by physical and chemical methods, in order to clarify what are the affecting factors for selection the best clay based soil for optimal restoration. In this regard, geological formation around Chogazanbil have been studies based on the previous research and in the highlighted locals as A, B, C, D, E, G. Investigations on alluvial deposits of R1, R2 carried out by XRD, XRF, grading, hydrometric and Aterberg boundary. Based on the obtained diagrams, the nonsandy soils contain most of the silty fine grains. This will assume the highest paste index or PI corresponds to sample C and the lowest PI to sample R1. Inflation potential was also found in pastures B, D, E, R1, R2 based on paste index. However, the swelling potential of C and G3 mines was moderate. The results of mineralogical experiments showed that calcite and quartz are the most minerals in the studied soils samples. Calcite in the soil, besides being a deterrent to inflation and divergence due to the presence of clay minerals, can also increase the strength of clay materials. The soils were poor quality in terms of high quality clay minerals such as kaolinite and montmorillonite. XRD analyses show that the amount of silica, in sample E is optimal for clay preparation. This effect makes the clay with high adhesion and strength coefficient produced by calcite. The amount of chlorine and sulfate ions in the soils of B, C, D, E, and G3 areas were also higher than the permitted amount. Sodium and potassium chloride have an important role in swelling and divergence of clay because of monovalent ions in their crystal chemistry. Indeed the soils were divergent soils, due to their salt content and therefor, show little resistance to humidity and water. Discriminating of that, excessive calcite in the samples can be considered as a deterrent agent for rapid inflation. Sulfate can also cause adhesion in the vicinity of moisture and by the latent phenomenon of fracture. The coherence factor of clay structures can effects of this phenomenon and probably most damages on the clay based structure of the Choghaznabil area are the result of this point. Based on the results obtained, the soils reservoirs around Choghaznabil are far from common daily standards for norm brick making, but after refining and valuable preparation, followed by processing, molding and drying can optimally have better mechanical behavior and might be reused for construction. Moreover, the soils samples from R2 and G3 have appropriate grain size than other soils around the area. In this case of study, the best recipes can be achieved by mixing this kind of soil with sand and straw for avoiding the cracks, which had considerable deterioration factor in the vicinity of the humidity and moisture. Optimum handling and processing of the clays from R2 and G3 areas are capable to improve the mechanical behavior of the repaired clay for reusing in the restoration of Choghazanbil.