左江花山岩画面层抢险加固材料的选择与研发

由于绘制崖壁的地质、气候等因素,左江花山岩画出现了开裂等严重病害。在比较所有可选材料的性能后选择了天然水硬石灰作为面层抢险加固黏结材料,经过实验室配方研发遴选、无岩画表面实验检测、有岩画表面工艺验证与质量评估体系研究,明确了花山岩画抢险加固采用天然水硬石灰制备的材料体系及其工艺,为全面展开抢救性保护工程提供了技术保障。     

基于仰韶水泥的砂岩石窟裂隙灌浆材料室内筛选研究

偏高岭土是高岭土经高温脱水后形成的一种高活性的人工火山灰材料,铝酸钙膨胀剂(AEA)是以一定比例的优质高铝熟料、无水石膏等无机材料共同粉磨而成的抗裂防水膨胀剂。在研究"仰韶水泥"的过程中发现,在烧料礓石水硬石灰中添加偏高岭土后,可有效提高水硬石灰结石体的强度,缺点是收缩变形较大。本研究基于对"仰韶水泥"的研究,结合砂岩石窟及其裂隙加固的特点,通过室内研究在烧料礓石水硬石灰中添加不同比例偏高岭土和膨胀剂AEA后浆液的流动性、凝结时间、收缩率、龄期强度等基本性能,初步筛选出了适宜砂岩石窟裂隙加固的灌浆材料及配比。     

广西宁明花山岩画保护技术现场试验部分初步研究

通过实地试验,筛选出适合花山岩画保护的岩体开裂注胶粘接加固、岩画表层片状剥离治理、岩画鳞片状剥落表层渗透加固的材料及工艺,从而为大面积岩画本体保护提供科学的试验依据。     

广西宁明花山岩画病害勘察研究

在常年自然营力以及环境变化等因素共同长期作用下,花山岩画岩体开裂、片状剥落、岩画颜料层褪色脱落、岩溶覆盖、生物风化等病害程度明显加剧,给花山岩画造成了巨大破坏,威胁着岩画的长期保存,本文从花山岩画病害类型分析、发育程度、分布特征和产生原因等方面详细调查出发,总结出科学勘察花山岩画的方法,为后期岩画保护治理工作提供详细必要的基础资料和依据。     

聚丙烯纤维、偏高岭土和细砂对水硬石灰改性的研究

为改善水硬石灰的力学性能,适当提高其抗压与抗折强度,本工作设计并制备了添加不同配比的聚丙烯纤维、偏高岭土和细砂的水硬石灰,并对其力学强度,矿物成分和微观形貌进行试验研究。结果表明,单独添加30%偏高岭土、0.1%聚丙烯纤维或者50%石英砂的水硬石灰抗压强度相对较高。在偏高岭土-水硬石灰中,单独添加0.1%短长度聚丙烯纤维或者共同加入0.1%聚丙烯纤维和50%石英砂可以提高其长期抗压强度。添加聚丙烯纤维还可以提高水硬石灰抗折强度。钙铝水合物不稳定和长期抗压强度下降有关,添加1%聚丙烯纤维可以提高碳酸化反应。聚丙烯纤维还能够增大水硬石灰内部的摩擦力和锚固力。在南京市罗廊巷太平天国建筑壁画保护中,对于地仗层脱落部位的修补采用改性水硬石灰进行了局部应用,效果良好。     

广西花山岩画颜料脱落和褪色原因分析

花山岩画是研究我国百越民族古代社会历史最重要、最直接的资料,岩画颜料脱落和褪色是岩画的主要病害。任何文物发生病害既与其制作材料和工艺有关,也与其保存环境因素相关。本工作在花山岩画制作材料和工艺分析研究以及区域环境特点分析的基础上,分析并讨论了岩画颜料脱落及褪色发生的原因。结果表明,岩画颜料层病害主要是受物理风化(温差变化、高湿度与光辐射)、化学风化-溶蚀作用和胶结材料老化引起;颜料褪色是由于岩画颜料表面覆盖泥质薄膜和颜料胶结材料老化导致颜料颗粒脱落致使颜料色彩饱和度降低,岩画颜色变淡变暗。     

广西宁明花山岩画颜料胶结材料分析研究

花山岩画是研究我国百越民族古代社会历史的重要资料。岩画颜料中胶结材料分析是判断岩画制作工艺、岩画颜料脱落、褪色原因以及岩画病害治理的重要依据。本工作利用三维视频显微镜和材料显微镜、红外光谱仪、激光拉曼光谱仪、气相色谱质谱仪(GC-MS)等,主要分析了花山岩画颜料胶结物成分。结果表明,岩画颜料胶结材料为植物性粘合剂;颜料样品中含有分布均匀的草酸钙,草酸钙的形成与颜料使用植物性粘合剂有关。     

水在广西花山岩画风化病害中的作用及其防治对策

花山岩画位于广西壮族自治区宁明县,其保存环境特征是高温潮湿多雨,花山岩画受环境因素作用,岩画颜料及岩石风化明显,风化类型复杂多样,有化学风化、物理风化和生物风化,同时存在、相互影响。它们均与水分有着直接的或间接的关系,因此水的防治是治理岩画风化病害的前提。本工作在水分来源及岩画保存地区地形地貌现场调查的基础上,通过水质分析系统研究了水在岩画风化病害过程中的作用。提出了花山岩画防水治水原则,并结合地质环境和特殊的地形地貌,将整个治水区域划分为山体山顶治水、溶蚀洼地治水、岩画立壁治水三个区域。根据其不同的渗水机制,分别采用盖、堵、排、导相结合的综合防水治水方法。由于岩画病害机理极其复杂,花山岩画防水、治水的难度很大,必须采取区别对待,综合治理的方法。     

左江花山岩画文化景观突出普遍价值解读——杰出的岩画艺术与独特的文化景观

2016年7月,在第40届联合国教科文组织世界遗产委员会会议上,左江花山岩画文化景观成功列入《世界遗产名录》。左江花山岩画文化景观既是中国世界文化遗产中的第一个岩画遗产,也是我国第一个"有机演进的残遗(或化石)景观"这一文化景观子类型的遗产地。目前在左江流域共发现80余处岩画点,它们沿左江及其支流明江密集分布。其中位于崇左市宁明县、龙州县、江州区及扶绥县境内,密集分布的38处岩画,被选择纳入3个遗产区申报世界文化遗产。左江花山岩画的突出特点主要体现在独特的图像表达系统、艺术创作所达到的美学成就、杰出的作画技术等方面。左江花山岩画文化景观是岩溶地貌中、以岩画为核心、利用特定的自然环境而形成的"自然与人的共同作品"。正是在岩画艺术与文化景观这两个范畴都体现出的优秀品质的交融,造就了该遗产在全球范围内的突出普遍价值。     

亟待保护的宁明花山岩画

宁明花山岩画,据碳十四年代测定,其年代为距今1680年至4200年。花山岩画在几千年的自然地质营力的作用下,产生了严重的病害。近年来,花山岩画的保护受到了社会的关注。2004年4月,国务委员陈至立批示,加强对花山岩画保护的指导。同年5月,国家文物局局长单霁翔、广西壮族自治区政府副主席吴恒进行现场调研,对花山岩画的保护与利用作出重要指示。2006年12月,花山岩画列入《中国世界文化遗产预备名单》。     

花山岩画岩体开裂机理统计分析

岩体开裂是危害花山岩画最严重的病害,会对岩画造成毁灭性的破坏。为制定有效的灌浆加固措施,在对岩体开裂成因及影响因素分析和现场调查的基础上,做了统计分析。结果表明:1)岩画区共有418处开裂病害,开裂岩体以风化开裂体为主,占69%,且构造开裂体的厚度大于风化开裂体;2)构造开裂体的钙质、钙质与泥质共同充填比例为78%,高于风化开裂体的52%;3)构造裂隙和风化裂隙的张开度均以小于6mm为主,可知当张开度大于6mm时,开裂体将发生剥离掉块;4)风化开裂体的危险性I级、Ⅱ级所占的比例为57%和22%,小于构造开裂体的64%和27%,但风化开裂体多发育于岩画存在部位,易出现开裂和掉块,破坏更大;5)构造开裂体的厚度较大、裂隙连通性好、危险等级高,而风化开裂体厚度较薄、裂隙贯通性差、危险等级较高。本研究结果可为开裂岩画岩体灌浆加固及后期修复提供理论依据。     

Characterization of Hydraulic Lime Mortar Containing Opuntia ficus-indica as a Bio-Admixture for Restoration Applications

Many successful and long lasting structures that contain lime mortars are hydraulic in nature. Organic admixtures are added to lime mortar mix to modify their fresh and hardened state properties. The present work proposes plant extract as bio-admixture for repair mortar towards the protection of heritage structures. The effect of cactus extract on the properties of hydraulic lime mortar is studied. Mortar´s composition is selected with respect to the composition of historic mortars and modern restoration practice. Cactus extract was added to the lime sand mixture with varying concentrations (25%, 50%, 75%, and 100%) and with different fermentation periods of 0, 1, and 2 days The consistency and workability of modified mortar, mechanical behavior, water absorption, porosity, and water/salt absorption through capillary rise, salt crystallization have been studied. Micro structural properties of the resulting mortar have been evaluated by XRD and FT-IR to identify their mineralogical composition and morphology by SEM-EDX. It is observed that addition of 75% cactus extract with 1-day fermentation produces maximum positive effect on the strength and durability properties of lime mortar. It improves the mechanical characteristics, limits water and salt absorption by capillarity into mortar and also show resistance to salt crystallization cycles.     

Characterization of pozzolanic lime mortars used as filling material in shaped grooves for restoring member connections in ancient monuments

This article presents a set of mechanical characteristics for a pozzolanic mortar consisting of hydrated lime and metakaolin, which is used as filler between metallic connectors and marble blocks during restoration activities of ancient monuments in Greece. Mechanical properties include the uniaxial and triaxial compressive strength, the indirect tensile strength, the bending strength, the elastic modulus and Poisson’s ratio, and a shear failure criterion. Cored cylindrical specimens are used for determining the uniaxial and triaxial compressive behavior and the indirect tensile strength of the mortar, thus ensuring the repeatability of the experimental results. The triaxial tests indicated a plastic behavior of the mortars under study, enabling them to perform well in conditions of high shear forces. Calcite and hydraulic components formed in the setting procedure contributed to the plasticity of the final mortar. The mechanical properties that were developed can be utilized to model material behavior and failure under conditions of confined or triaxial loading. The development of a shear failure criterion for a pozzolanic mortar is a substantial accomplishment that has not been previously reported in the international literature.     

Analytical Investigations of Traditional Masonry Mortars from Ancient City Walls Built during Ming and Qing Dynasties in China

With the development of China’s economy, the protection and conservation of ancient buildings were put on the agenda. However, the current understandings on Chinese traditional mortars are limited and rarely reported in the literature. In this article, the authors investigate seven ancient city wall sites built during the Ming and Qing dynasties (1368–1841 AD) in situ, and subsequently the laboratory analysis were carried out on the collected mortar samples. The characterizations of mortar samples were performed using digital microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), simultaneous thermal analysis (TG-DSC), as well as wet chemical analysis. The analytical results show that pure lime mortar was widely used in construction during the Ming and Qing dynasties, and it was also a common practice adding sticky rice soup into slaked lime to form sticky-rice lime mortar during preparations. This organic-inorganic composite material could effectively improve mechanical strength of the lime mortar. Moreover, it was first found that the sticky-rice lime mortar sample from Kaifeng ancient city wall contained very fine quartz aggregates, with an approximate binder/aggregate ratio of 1:1. The appearance of this type of mortar probably indicates a great development of Chinese traditional mortars during the mid-19th century.     

我国传统镁质石灰初步研究

对我国从明代到民国的建筑灰浆的化学成分、矿物成分等分析发现,部分砌筑及抹灰灰浆为镁质石灰,MgO含量达到5%~26%。特别是取自河北、北京等地长城的传统石灰样品全部为镁质石灰。镁质石灰与钙质石灰比较,具有强度高、吸水率低的特点,从而具有更佳的抗冻融性能。此外,镁质石灰收缩低、易于施工。镁质石灰煅烧需要的温度低于钙质石灰,能耗低。鉴于传统镁质石灰在中国的研究尚为空白,建议系统地开展镁质石灰研究,研究内容包括原材料类型及分布、煅烧温度、消解方式、配比优化等。同时宜研究镁质石灰在严重大气污染下的耐久性及镁质石灰相关建筑遗产的保护修复技术等。     

Kinetic effect of carbonic anhydrase enzyme on the carbonation reaction of lime mortar

The effect of carbonic anhydrase enzyme on the precipitation kinetics and phase transformations of calcium carbonate, and on the strength development of lime mortars has been investigated with saturated lime solutions, lime pastes and lime mortars under atmospheric conditions. The results clearly show that carbonic anhydrase catalyzes the reaction between carbon dioxide and aqueous lime, and increases the rate of calcium carbonate crystallization, the yield of the carbonation reaction and mortar strength at early ages. This is most likely a kinetic effect associated with the increased rate of carbonate ions supply to the solution by the enzyme. In addition, this enzyme favors the formation of stable calcite and significantly modifies its morphology by developing new crystal faces. These results suggest a novel approach for accelerating the hardening of lime mortars using carbonic anhydrase enzyme, which may offer a potentially novel approach with significant benefits on the applications of lime mortars in architectural heritage conservation as well as in construction.     

Effect of natural polymers from cissus glauca roxb on the mechanical and durability properties of hydraulic lime mortar

The tradition of using lime as a binder has been in practice over the centuries and is cited in the architectural feats of all kinds of civilizations. Besides the basic ingredients of lime, sand and water, organic admixtures were also mixed into the mortars to modify fresh and hardened state properties as well as to enhance its durability. The motivation of the present study was to develop a replacement of synthetic admixtures by the bio-admixtures. The plant extract of Cissus glauca Roxb (CGR) which is being used in ancient temples and monuments in Kerala has been tested as admixture in varying concentrations and fermentation periods in lime mortar mix. The admixture is polysaccharide rich and a moisturizing agent.

Tests were conducted to measure changes in microstructure of the mortar; fresh state properties such as setting time and workability, mechanical properties such as compressive strength and flexural strength. Also, physical characteristics of admixture modified mortars such as bulk density, porosity and water absorption were also determined. Morphological analysis using SEM with EDX, mineralogical analysis using XRD and organic analysis adopting FT- IR have been done to validate the results of mechanical and physical tests. Capillary water and salt absorption by suction and resistance to salt crystallization cycles were measured as an indicator of durability properties.

The admixture modified mortar resulted in increased mechanical properties and reduced water absorption. It also limits the capillary rise of water and salt intrusion through the hydrophobic nature. The admixture modified mortar have also offered better resistance against the damaging action of deteriorating salts such as sodium chloride and sodium sulphate crystallization cycles. Polysaccharides and proteins in the plant extract interact with the calcium hydroxide of slaked lime and forms complexes. Hence the, natural polymer has increased the durability of hydraulic lime mortars used for repair and it could be a natural alternative to synthetic admixture.     

Qadhat—a comparative study of ancient and new lime mortar from the Marib province/Yemen

Qadhat is the name for a lime mortar in Southern Arabia. Its usage has a long tradition. This work describes physical and mineralogical properties of ancient, historical and new samples, which seem to have been produced the same way. XRD, thin sections and SEM analyses show the similarity of the material. It consists of aggregates of volcanic material that are rich in volcanic glass and lime as binder. The production process includes several hours of crushing the material, which produces fine-grained splinters of aggregates in the binder matrix and gives the mortar a high stability. A weathering test with sodium sulphate on different samples confirms that the stability of this mortar is the result of the production process.     

Characterization of archaeological lime mortars in a Ming dynasty tomb: A multi-analytical approach

Lime mortars have played an important role in constructing ancient Chinese masonry structures, including city walls, buildings, and tombs. A tomb built with lime mortars and stones belonging a Ming high-ranking official, Xu Jie, was discovered in Huzhou City of China. Eight different samples from Xu Jie’s tomb, representing four types of lime-mortar-based materials: joint mortar between stone bricks, bedding mortar, grouting mortar, and plaster mortars were collected for analysis and comparison. The characterization of the construction materials has therefore become of primary importance. The function of each mortar was reported and studies into the micro-textural features and mineralogical compositions of those mortars were performed via a multi-analytical approach. The joint mortars were all found to be aerial lime mortars with predominately lime. The bedding mortar was found to consist of lime, soil and sand, typical of a tabia mortar. The grouting mortar was found to consist of lime and ground contact metamorphosed limestone. Analysis of plaster sample taken from the roof of the main tomb identified the presence of calcium stearate/palmitate, indicating the usage of plant-based tung oil as an additive. The analytical results will promote our understanding of Ming architectural technology and craftsmanship, and provide critical information for the conservation of Xu Jie’s tomb.     

Characterization of ancient building lime mortars of Anhui province,China: A multi-analytical approach

The characterization of lime mortars has become of primary importance in order to obtain information about the raw ingredients and building technology of ancient masonry structures. Five different samples from Anhui province, China, representing two types of lime mortar-based materials: joint mortars between the bricks of the city wall and lime mortar sealing a tomb coffin, were collected for analysis. Archaeological information about the samples was reported and studies into the microtextural features and mineralogical compositions of those mortars were performed via a multi-analytical approach. The joint lime mortars between the bricks of city walls, including Mingzhongdu city wall, Mingzhongdu Xihua gate foundation, Zhengyangguan city wall and She county city wall, were found to be aerial lime mortars. The lime mortar from Nanling Tieguai Song dynasty tomb was analysed and found to be a pozzolanic mortar consisting of lime, clay, sand and cocciopesto-like materials. The analytical results serve as a critical reference for the maintenance and restoration of ancient city walls in Anhui province, and as a starting point for searching for ancient Chinese pozzolanic mortars and technology for making those mortars.