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Wang Y.B.,CAS Institute of Geology and Geophysics | Wang S.J.,CAS Institute of Geology and Geophysics | Li L.,Chinese Academy of Culture Heritage | Chen R.,Harbin Institute of Technology | And 2 more authors.
5th Asia-Pacific Conference on Unsaturated Soils 2012 | Year: 2012

The protection of earthen relics in moist areas is a key issue of cultural heritage conservation, Potassium Silicate (PS) infiltrated reinforcing the earthen relic is also a hot issue. PS is infiltrated into soils under constant pressure and reacts with clay mineral to protect earthen relics. But the effect of PS reinforcement may be different because of high degree of saturation in moist areas. In this paper, two series of specimens were designed to investigate the potential of PS reinforcing the soils with high degree of saturation, mainly focusing on shear strength of unsaturated soils at constant water contents. The specimens are made by compaction at the specific water content. After that, the gravimetric water contents of specimens are controlled at 13% 17% 19% 21% and 25%. One group of specimens is directly sheared at constant water contents using direct shear apparatus under 100kPa and 300kPa, the other group is reinforced by PS and then sheared at the same water content under same vertical pressure. According to the soil-water characteristic curve derived from the mercury intrusion porosimetry test, the shear properties of two groups are summarized and analyzed at different initial matric suctions. These results justify that PS can reinforce earthen relics in moist areas.

Tian X.,Beijing University of Chemical Technology | Tian X.,Chinese Academy of Culture Heritage | Li N.,Chinese Academy of Culture Heritage | Zhang Z.,Chinese Academy of Culture Heritage | And 4 more authors.
Anti-Corrosion Methods and Materials | Year: 2013

Purpose: The aim of this study was to investigate the effectiveness of restoration of gold foils on Dazu Grottoes using different parylene coatings. Design/methodology/approach: The gold foil samples were applied with two types of parylene coating with six different thicknesses, C-10, C-15, C-20, N-10, N-20, N-25, respectively. Electrochemical impedance, surface morphology, and hydrophobicity properties were used to examine the behavior of the coatings. Findings: The results showed that an increase in electrochemical corrosion resistance was observed as the degree of coating thickness was increased for both C-parylene and N-parylene coatings. In addition, the surface morphology study, using 3D topography measurement, indicated that the surface roughness was decreased for all parylene coatings. Furthermore, the parylene-C coating was comparatively more effective than was the parylene-N coating. Originality/value: The results obtained from the three methods were in close agreement. This is an indication that the parylene-C coating can be used to restore the gold foils on Dazu Grottoes and to support future restoration and consolidation to be applied on site on the Grottoes. © Emerald Group Publishing Limited.

Tian X.,Beijing University of Chemical Technology | Tian X.,Chinese Academy of Culture Heritage | Ma Q.,Chinese Academy of Culture Heritage | Zheng M.,Beijing University of Chemical Technology | Li Z.,Beijing University of Chemical Technology
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2014

Many cultural relics adhered with gold leaf (e.g. gold foil) are found damaged seriously in recent years. In this paper, gold leaf was exposed in the imitating atmosphere of moisture SO2, NO2 and their mixture to investigate its corrosion possibility in environment atmosphere at ambient temperature. Following phenomena were observed. The gold leaf was corroded in all these three atmospheres, which is contrary to the common sense that gold can only be corroded in aqua regia at ambient temperature. In SO2 atmosphere, the main reason of the corrosion is the preferential oxidation of the impurity of Cu. In the atmospheres of NO2 and the mixture of SO2 and NO2, the main reason of the corrosion is the combination of the preferential oxidation of the impurity and the oxidation of gold itself caused by the high defect density stemmed from the severe cold deformation during its processing. The discovery that gold can be corroded in moisture acid atmosphere at ambient temperature expands the understanding of the character of gold, and provides beneficial guidance to the protection of culture relics and modern artworks decorated with gold foil. Copyright © 2014, Northwest Institute for Nonferrous Metal Research. Published by Elsevier BV. All rights reserved.

Wang X.-D.,Harbin Institute of Technology | Wang X.-D.,Harbin University of Science and Technology | Wang W.,Harbin Institute of Technology | Wang L.-A.,Chinese Academy of Culture Heritage | And 3 more authors.
Gongcheng Lixue/Engineering Mechanics | Year: 2011

The Cangzhou iron lion is the first batch important heritage site under state protection, and it is also an earliest and bigness cast iron historical relic by one pouring technology. In order to evaluate the seismic safety of the lion, a non-linear time-history analysis was performed with finite element program. After the geographical model of the lion was acquired by the method of 3D laser scanning, a finite element model was founded though meshing on the closed entity and then the response of the lion under 8 degrees of an unordinary earthquake action. The results show that the stress of both the lion and its brackets is less than the yield stress respectively, horizontal and vertical displacements are both on the small side, and the lion structure has sufficient seismic safety.

Zhou X.,Chinese Academy of Culture Heritage | Gao F.,Chinese Academy of Culture Heritage | Gao F.,Central South University | Zhang A.-W.,Capital Normal University | Zhou K.-C.,Central South University
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2012

Yungang Grottoes were built in the mid-5th century A.D., and named as a UNESCO World Heritage site in 2001. Most of the grottoes were built on the feldspathic quartz sandstones. They were seriously damaged due to the environmental impact. The main form of the weathering is the powdered weathering. The weathering conditions are generally characterized by electrical sounding, penetration resistance, molecular spectroscopy, etc. However, although these methods can give good results about the weathering conditions for a specified sample or site, they are not suitable for providing a global profile of the weathering conditions. The present paper provides a method for effectively and roundly assessing the overall powdered weathering conditions of the Yungang Grottoes based on hyperspectral imaging. Powdered weathering could change the structure and granularity of the sandstone, and thus change the spectral reflectance of the sandstone surface. Based on the hyperspectral data collected from 400 nm to 1000 nm and normalized by log residuals method, the powdered weathering conditions of the sandstones were classified into strong weathering and weak weathering. The weathering profile was also mapped in the Envi platform. The mapping images were verified using the measured hyperspectal data of the columns in front of the 9th and 10th grottoes as the examples. The mapping images were substantially fitted to the real observations, showing that hyperspectral imaging can be used to estimate the overall powdered weathering of the sandstones.

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