The Modifiction Research Of Two Kinds Of Traditonal Materials Used On Preservation Of The Stone And Earthen Cultual Relics

Conservation of heritage sites refers to all measures carried out to preserve the physical remains of sites and their historic settings. The aim of conservation is to preserve the authenticity of all the elements of the entire heritage site and to retain for the future its historic information and all its values. Conservation in practice involves treatment of damage caused by natural processes and human actions and prevention of further deterioration, using both technical and management measures. The conservation of stone and earthen cultural relics is an important domain of the nation's cultural heritage conservation in its current phase. Stone and earthen cultural relics are dispersed widely around the country, and are of rich types and categories. These include unmovable types, such as stone temples, cliff stone carvings, rock painting, ancient murals, ancient architecture, earthen architecture sites like The Great Wall, frontiers, passes, and ancient cities; and movable types, such as cultural relics made of stone, brick, and ceramic. There are a great amount of the remains of stone and earthen cultural relics in our country. As a type of extremely delicate cultural relics objects, they contain a great amount of precious historic information and the most important imaging data, such as politics, economy, art, architecture, technology in the past dynasties and so on. They are also to be regarded as the object specimens of ancient civilization and the physical carrier of the succession of national culture containing attraction and cohesion of national unity and cultural identity. Stone and earthen cultural relics are high-quality state property and very precious contemporary cultural tourism resource. The conservation of stone and earthen relics in recent years has become one of the primary foci of cultural relics conservators. Conservation needs are also becoming increasingly pronounced. The success or failure of conservation work depends on appropriate selection of conservation materials and technology, therefore the research and development of conservation materials and technology are technique difficulties for cultural relics conservators to tackle. The present research paper, through detailed analysis of conservation status and its existing problems of stone and earthen cultural relics, aims at deterioration characteristics and cause, by cognizing traditional building materials scientifically modifies two conservation materials that can be adapted to the repair and reinforcement of stone and earthen relics in dissimilar environments and types. The preliminary research displays that the type of these materials is easy to use for technology and safe to environment with no contamination and good ageing-resistant performance. The paper investigates the following conclusions and innovations:I. Research on the Flooring Material of the Qin'an Dadiwan Archaeological Housing Sites of Gansu ProvinceBased on the research of Doctor advisor, Professor Li Zuixiong, we used such instruments as scanning electron microscope (SEM), polarizing microscope (PLM), and X-Ray diffraction (XRD) to further analyze and study the flooring materials from the two Yangshao-period F-901and F-405human residential house sites in the largest scale and exquisite technology which were discovered in the later1970s in the Qin'an Dadiwan settlement of Gansu Province, and to research calcium concretions ("kunkur") and ginger nut found in native loess. The results revealed that F-901and F-405site flooring was made of light weight aggregate of deposited kunkur in fired loess as the aggregate and fired muddy limestone(locally called ginger nut) mixed with the appropriate level of red clay as cementing material, which was similar to modern light concrete. Meanwhile, we use the technique of carbon-14dating to date the period of house construction and the instrument of thermal expansion analyzer to measure discovered ceramic shards from the site and then assay the temperature of firing pottery in Yangshao-period at Dadiwan Site (Archaeological discovery finds there is existing in one kiln to fire kunkur, ginger nut and pottery). On this foundation, analyses were made and simulation and comparison experiments conducted on the hydratability of the fired ginger nut and fired kunkur, and the house flooring manufacturing technology. They show that fired ginger nut and fired kunkur from F-901and F-405flooring posses the dual qualities of non-hydraulicity and hydraulicity that could be the earliest concrete in human history.This paper also researched Tibetan aga soil used for constructing temple flooring and house flooring for thousands of years. aga soil is a siliceous limestone that is similar to ginger nut. But when Tibetan aga soil was used for building house flooring and ground flooring, it was only shattered into different levels of particles and then mixed with a proper amount of natural gum and had no processing of firing aga soil. Because unfired aga soil had no dual qualities of non-hydraulicity and hydraulicity, as a type of construction material, aga soil had a low strength, fast aging and was easy to damage. Therefore, by contrastive research of ginger nut, aga soil and European hydraulic lime, It provides us new thought to modify aga soil and ginger nut.II. Research on the Modification of ginger nut and Aga SoilsOn the basis of the research of the Dadiwan Yangshao-period house site flooring materials, using contrastive analysis of the two types of silicate materials in ancient Chinese architecture, ginger nut and aga soil, it was discovered that they have the same chemical components and physical characteristics. After being fired at a temperature of700-1400°C, ginger nut and aga soil possess the dual qualities of non-hydraulicity and hydraulicity. As the temperature rises, the non-hydraulic component rises and then falls, while the hydraulic component continuously rises according to a regular transformation process. The chemical and mineral components together with chemical and physical mechanics characteristics of the modified ginger nut and aga possess a nature similar to the hydraulic lime of Europe. By regulating their ratio to control the strength of repaired concretion, they could be used to reinforce restorations of relics made of stone, earth, brick, and ceramic. The success of the modification of ginger nut and aga soil is a successful example of using modified Chinese traditional material for cultural relics conservation and reinforcement that is promoted by national cultural relics conservation sector.III. Research on the Physical Mechanics Characteristics of Modified ginger nut and Modified Aga soilSince the1970s, the natural hydraulic limes (NHL) of NHL2and NHL5have been extensively applied to the repair of historic architecture in Europe and America. In this research, on the basis of studies of Chinese two traditional silicate construction materials, we researched and analyzed the physical mechanics of modified ginger nut and aga soil, as well as the influence of environmental elements. In carrying out comparison with two types of European hydraulic lime (NHL2and NHL5), it was found that after three hours of firing at1000°C ginger nut and aga soil acquired characteristics similar to those of the European hydraulic lime. Modified ginger nut and aga soil possess such basic characteristics as low shrinkage and deformation levels, high porosity, and good water and gas permeability; moreover, they have relatively strong resistance to freezing and melting, water stability, and the ability to resist the influence of temperature and humidity fluctuation and alkaline corrosion. At the same time, modified ginger nut and aga soil also possess the characteristic of intensity control of repair concretion. The research of chemical and physical mechanics characteristics of the modified ginger nut and aga lays the theory foundation of applying inorganic material to the conservation and research of stone and earthen cultural relics.IV. Applied Research on the Reinforcement of Cliff-earthen Cultural Relics With Modified ginger nut and Aga soilGinger nut and aga soil reinforcements have been used in conservation projects at the sites of the Yuan-dynasty capital in Inner Mongolia, the Bao'en Temple remains in Nanjing, and the Koguryo wall-painted tomb. Through experimental research of these reinforcements, it became clear that an appropriate amount of modified ginger nut or aga soil added to the soil of the remains raised the sites'erosion tolerance. The addition of the modified materials, in a different proportion, to the Koguryo wall-painted tomb ground achieved an effective reinforcement result. The modified ginger nut and aga soil is a material that can be adapted to the repair and reinforcement of stone and earthen relics in dissimilar environments and types. This is a new breakthrough of material selection research on the protection and reinforcement of stone and earthen relics.