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 lime carbonates in plasters from Teotihuacan,Mexico: preliminary results of cathodoluminescence and carbon isotope analyses

This study characterizes the degree of calcination of lime in lime plaster samples from Teotihuacan, the capital of a regional state in prehispanic Central Mexico. Lime plaster production consists of multiple steps, from the firing of raw materials to the mixing of lime and aggregate and the final application. While previous studies have focused on the compositional variability, specifically the recipe of lime plasters and mortars, the characterization of lime itself has not been sufficiently addressed. In this study, cathodoluminescence analysis coupled with petrographic and image analyses were employed to examine the degree of calcination of lime. The results of cathodoluminescence petrography were further examined through stable carbon isotope and ¹⁴C measurements. It appeared that the results of cathodoluminescence analysis are consistent with those of other analytical methods and that there are diachronic changes in the degree of calcination of lime among lime plaster samples. This implies changes in the organization of lime production, specifically the consistency in the control of firing temperature.     

Technology and decay of magnesian lime plasters: the sculptures of the funerary crypt of Palenque,Mexico

The full-relief lime plaster sculptures of the funerary crypt of Palenque, Mexico, suffer from advanced decay due to the cave-like environment in which they are located. Macroscopically, the sculptures have a soft consistency, but there is a hard crust over their surface. Some of the features observed by microscopy are the neomorphism of minerals as a consequence of permanent water seepage, and the formation of wide shrinkage cracks as a result of drying. The mineral hydromagnesite Mg₅(CO₃)₄(OH)₂·4H₂O was identified by X-ray diffraction and microscopy; its relation with the shrinkage observed in the samples and its possible role in the decay of the sculptures are discussed in this paper. A short discussion is also made about the likely raw materials that were employed to manufacture the sculptures.     

陕西旬邑西头遗址出土彩绘白灰面的成分和工艺分析

对陕西旬邑县西头遗址出土的彩绘白灰面进行了成分和制作工艺分析。采用偏光显微分析、扫描电镜能谱、X射线衍射,拉曼光谱分析了该彩绘面的颜料和石灰层成分,采用气相色谱-质谱联用技术(GC-MS)分析了该彩绘面的胶料成分。结果表明,该彩绘面的颜料由铁红,铁黄和绿土构成。白灰层由碳酸钙构成,部分样品中存在双层白灰层。GC-MS分析表明,该彩绘面的胶料含动物胶,可能还含蛋类。通过比较研究发现,旬邑彩绘白灰面的制作工艺和与后期壁画制作工艺相似,对其组成和工艺的研究将有助于探索先周时期关中地区壁画的起源和发展。     

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。     

Unveiling the Use of Creta in Roman Plasters: Analysis of Clay Wall Paintings From Brixia (Italy)

The paper describes the analysis of a particular kind of plaster from the walls of the Roman Sanctuary (first half of the first century bce ) in the centre of Brixia (now Brescia, Italy), which is an outstanding example of Roman Republican architecture. The walls were plastered and painted with different patterns, imitating marble panels and curtains. Optical microscopy on thin sections, X‐ray diffraction and infrared spectroscopy were performed on several samples of the plaster in order to reveal the execution technique. The palette consisted of glauconite, celadonite, Egyptian blue, and red and yellow ochres. In some cases, an organic compound, possibly a lipidic compound, was present in the external paint layer, as a surface treatment. The plaster contains two superimposed coats: the render coat with lime binder and sandy aggregate; the finish coat with a clay fraction (illite, chlorite, kaolinite), together with calcite from slaked lime and grains of quartz, silicate and carbonate rocks. Although Vitrivius' De architectura reported the use of creta (clay) as daub smeared on reed vaults, the Sanctuary of Brixia represents the first documented use in Roman buildings in a painted plaster laid on a stone masonry wall.     

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.     

Multi‐analytical Studies of Archaeological Chinese Earthen Plasters: The Inner Wall of the Longhu Hall (Yuzhen Palace,Ancient Building Complex,Wudang Mountains,China)

The Yuzhen Palace is one of the nine palaces in the Ancient Building Complex built by order of the Yongle Emperor during the Ming dynasty. The buildings were built with dressed black bricks. As a result of the planned national South–North Water Diversion project, the water level in the Danjiangkou Reservoir that surrounds the Yuzhen Palace was expected to rise by approximately 15 m. To avoid submersion of the site, three gates were elevated by 15 m in 2013 and other buildings dismantled, for later reconstruction. The characterization of the construction materials has therefore become of primary importance. Here, we present results on the plasters of the Longhu Hall. The analysis of materials involved a multi‐analytical approach combining optical and electron microscopy with X‐ray and vibrational spectromicroscopies and thermogravimetry. The results indicated the use of two earthen plaster layers and a whitewash finish coating applied over a thin preparatory intermediate layer to improve the adherence of the finish coating to the earthen plaster. Ramie and straw fibres identified in the earthen plasters were added to reduce shrinkage and cracking during drying. The raw materials used and the application technique pointed to a well‐established construction industry using traditional earthen building materials together with lime technology.     

Lime Burning in Clamp Kilns in Scotland's Western Central Belt: Primitive Industry or Simple but Perfectly Adequate Technology?

Lime is a fundamental component in many industrial, agricultural and chemical processes, and is itself produced by an industrial process, namely, the heating in kilns (calcining, or more colloquially ‘burning’) of calcium carbonate rock or other carbonate material. Research and literature on lime burning in Scotland, based largely on lime production in Scotland's eastern Central Belt, are dominated by the view that lime burning in draw kilns is the paradigm for Scottish lime production. Other parts of Scotland, however, largely or completely ignored, draw kilns in favour of simpler clamp kilns, even in major industrial sites of lime production. This paper reports our map- and field-based surveys in Scotland's western Central Belt, which clearly point to the enduring importance and almost exclusive use of clamp kilns in that area's historical lime-burning industry.     

Plasters from Different Buildings of the Sacred Precinct of Tenochtitlan (Mexico City): Characterization And Provenance

In this work, we present the results of the characterization of 20 lime plaster samples taken from the Sacred Precinct of Tenochtitlan (Mexico City), the ancient capital of the Aztec empire. The samples come from different buildings of this precinct (A, B and D) and from the west façade of phase VI of the Templo Mayor pyramid. The objective of the work is to characterize the plaster samples, to understand the raw materials used, and to evaluate the presence of similarities and differences among the samples in the building techniques and raw materials employed. All the samples were studied with OM, SEM–EDS and LA–ICP–MS. The study provided evidence of the plastering and replastering practice in the same constructive phases. The results of the analyses showed the existence of important similarities and differences among buildings and constructive phases in the Sacred Precinct. In order to understand the provenance of the limestone used in the plasters, the lumps and the binder of the samples were analysed. The results were compared with those of the limestone outcrops located in central Mexico. The provenance study showed that all the limestone used in the construction of the analysed buildings of Tenochtitlan's Sacred Precinct comes from the Tula region.     

Chemical and Microscopic Study of Masonry Mortar in Ancient Pagodas in East China

Ancient mortars played a crucial role in the construction of historical architectures due to their physical and chemical compatibility with traditional building materials such as stones and bricks. Therefore, the analysis and optimization of the ancient mortar formula are significant in the restoration and preservation of historical sites. In this work, 20 mortar samples selected from five ancient stone pagodas in Zhejiang Province, China, were analyzed. The results showed that mud, lime-soil mortar, lime-sand mortar, and lime-gypsum mortar were used as binders in these pagodas. The Ca(OH)₂/aggregate ratio ranging from 0.3 to 2.7 was usually used to prepare lime mortar. Protein and polysaccharide were also found in some samples.     

X‐ray Diffraction and SEM Investigation of Wall Paintings Found in the Roman Temple Complex at Horvat Omrit,Israel

In the present study, the fragments of wall painting found in the Roman Temple Complex at Horvat Omrit were analysed for the first time using the non‐destructive techniques of X‐ray diffraction (XRD) and scanning electron microscopy (ESEM) equipped with energy‐dispersive X‐ray spectroscopy (EDS). The application of these methods enabled unambiguous identifications of the pigments and plaster components of the samples. Quantitative information on mineral composition, crystallite size and elemental composition of each studied paint layer and plaster was collected. Based on the results of the XRD and EDS analyses, the green pigment was identified as celadonite. It was revealed that the Egyptian blue pigment does not contain impurities of tin and lead, and this excludes the use of bronze scrap in its synthesis. Comparison of the mineral composition of the paint layers indicates that a wider palette of colours was obtained by mixing the available mineral pigments. The study of cross‐sections of painted specimens revealed the usage of slaked lime for plastering. The obtained results give a new insight into the wall painting technique employed by ancient artists at Horvat Omrit, in northern Israel.     

中国明代木质古建西安鼓楼彩绘的分析研究

鉴于有关中国木质古建彩绘材料及技术的研究报道较少,本工作通过光学显微镜、扫描电镜能谱(SEMEDX)、X射线衍射及气相色谱质谱(GC/MS)分析方法,对建于公元1380年的中国西安明代鼓楼木建表面彩绘样品进行了科学检测研究,分析了其中的无机材料组成及彩绘所用粘合剂,并收集了所涉及到的相关历史资料。分析结果表明,木建表面彩绘的材料组成和制作技术与历史调查获得的信息完全吻合。地仗层主要由粘土、石灰、干性油(桐油)及纤维织物组成,且地仗层保持最初的原材料。颜料分析结果显示,尽管修复时所使用的粘合剂与最初建造时的粘合剂完全相同,但目前彩绘的颜料即有原来使用的材料,也有十八世纪修复时所使用的材料。     

水硬性石灰改性土修复加固材料性能研究

针对土遗址土体坍塌、残缺等病害,为选择更好的土遗址修复加固材料,通过遗址土中添加水硬性石灰进行改性,分析检测水硬性石灰改性土修复材料的性能,并与石灰改性土材料性能进行对比分析。研究结果表明,与石灰改性土性能相比,水硬性石灰改性土修复材料夯土收缩率小、水稳定性好、抗压强度大和强度增加快、耐冻融性好;其性能优于石灰改性土材料的性能,适合土遗址土体坍塌、残损病害的修补加固,其研究成果为土遗址的保护修复加固提供科学依据。     

水硬石灰在花山岩画加固保护中的应用研究

水硬石灰兼具石灰和水泥的优点,低收缩、耐盐、适中的抗压和抗折强度、水溶盐含量低,同时与传统的砖石建筑兼容性好,是一种天然、无污染、耐老化的无机材料。本工作针对花山岩画的开裂特点制订出相应的力学参数要求,配制出两种不同的水硬石灰砂浆,并对这两种砂浆的力学性能进行了分析。同时探讨了不同养护条件对水硬石灰砂浆拉拔强度的影响。现场试验结果说明,填补粘结材料可以提供一定的粘结强度,并且具有使用方便,污染小的特点,可用于花山岩画开裂岩体应急保护加固处理。     

天然水硬性石灰在不同碳化条件下的水化反应

为了探究不同碳化条件对天然水硬性石灰水化过程的影响,继而认识到养护条件中的碳化作用对天然水硬性石灰早期强度和养护时间的影响,模拟制备了不同碳化条件下的样品,用X射线衍射(XRD)、热重分析(TG)、红外光谱(IR)、扫描电子显微镜和X-射线能谱分析(SEM-EDX)测试和比较养护前后天然水硬性石灰成分、结构、形貌的变化。研究表明,天然水硬性石灰水化生成水化硅酸钙(CSH)、氢氧化钙(Ca(OH)_2)的反应与CSH、Ca(OH)_2的碳化反应同时进行,并且Ca(OH)_2的碳化速率大于水化反应生成Ca(OH)_2的速率。随着养护龄期增加CSH逐渐由细小的针棒状结构生长为粗大的棒状结构,随后又逐渐变短并最终完全碳化为方解石晶型的碳酸钙(CaCO_3)形貌。天然水硬性石灰水化产物的碳化作用能促进其水化反应进程。     

CHARACTERIZATION AND PROVENANCE OF LIME PLASTERS FROM THE TEMPLO MAYOR OF TENOCHTITLAN (MEXICO CITY)

In this work, we present the results of the analyses of 20 lime plaster samples taken from the Templo Mayor (Great Temple), the main pyramid of Tenochtitlan (Mexico), the ancient capital of the Mexicas. The samples were analysed to recover information on the mixtures used in the fabrication of the plasters and for the provenance of the raw materials (in particular, limestone) used to make the plasters. The characterization of the samples was done by OM, SEM/EDS, XRF and LA–ICP–MS analyses, while the identification of the provenance of raw materials was done by studying the lumps present in the samples with LA–ICP–MS. The objective of the study was to establish if there was a relationship between changes in the construction techniques employed in the pyramid over time and if there were changes in the provenance of the raw materials. Six different construction phases of this pyramid are analysed, showing the similarities and differences among them, mainly based on differences in the sieving of the aggregates and in the raw materials employed. The provenance studies of the limestone used to make the plasters demonstrated that all the limestone comes from the Tula region.