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.     

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.     

传统水硬性灰浆性能的影响因素综述

水硬性灰浆是性能优良的传统建筑材料,其相比于气硬性灰浆,有更好的防水性、透气性、耐冻性、耐盐结晶性和机械强度等,适合作为古建筑的修复材料。本研究对影响传统水硬性灰浆性能的因素进行归纳综述,探讨无机物(胶凝材料、骨料、水)、天然有机物(多糖类、蛋白质类、油脂类)、养护条件等对水硬性灰浆性能的影响。其中,无机物对水硬性灰浆的性能影响一方面取决于胶凝材料的特性,另一方面取决于灰浆中不同无机组分间的比例;在水硬性灰浆中加入多糖类有机物可提高灰浆力学性能,加入蛋白质类有机物可提高防水性和孔隙率,加入油脂类有机物可大幅提升防水性、耐久性;在高相对湿度条件下养护水硬性灰浆可提高其机械强度,而低湿度条件下养护的灰浆则更具耐久性。本研究成果可为认知、揭示传统水硬性灰浆的科学价值,研究、开发新型古建保护修复材料提供参考与启示。     

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.     

Calcareous nannofossils in medieval mortar and mortar‐based materials: A powerful tool for provenance analysis

Calcareous nannofossils—very small‐scaled marine microfossils—occur in many archaeological materials. Foremost, these include limestones used in masonry, material which has not experienced significant modification by humans. Poorly documented are nannofossils in mortars, because the burning process of quicklime requires the heating of the raw material to > 800°C. Here we focus on calcareous nannofossils in mortar and mortar‐based samples of four medieval buildings in northern Germany. The study documents the presence of nannofossils in historic mortars. It supplies evidence for the provenance of the mortars used, thereby introducing a new tool for mortar provenance studies.     

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.     

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。     

Mineralogical and Mechanical Properties of Masonry and Mortars of the Lucknow Monuments Circa the 18th Century

The Lucknow monuments of the 18th century are large masonry structures built using thin burnt-clay bricks (Lakhauri) and lime-crushed brick aggregate (surkhi) mortars. Investigations were carried out to characterize the engineering properties of old masonry materials and new mortars being used for renovation work. Mechanical properties of reclaimed Lakhauri bricks were found comparable to good quality contemporary bricks of the region. Moreover, X-ray diffraction (XRD) and scanning electron microscopy–energy dispersive X-ray spectrometry (SEM-EDS) analyses indicated that mineralogical composition is not too different, except for few minerals. The lime-surkhi mortar used in old masonry work was found to be lime-rich with binder to aggregate ratio of approximately 1:2 to 3 by volume. The renovation mortar had poor hydraulic property as compared to old mortars indicated by thermal gravimetric analysis–differential thermal analysis (TGA-DTA) analyses. The compressive behavior of multi-wythe recreated Lakhauri masonry prisms was characterized with low compressive strength, low modulus, and significant deformability which result in lower stress demands imposed on the structural assemblages by various environmental forces.     

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.     

Historical materials from the post-Cistercian abbey in Kamieniec Ząbkowicki (southwestern Poland)—application of mineralogical methods for identification of source of raw materials

In this paper, we use a set of methods applied for geosciences to reveal the provenance of raw materials and historical aspects of technology of lime production from the post-Cistercian church (southwestern Poland). Two types of building stones (mica schists and sandstones) and two groups of mortars, related with two different construction phases (Gothic and Baroque), were used for construction of the church façade. Principal difference between binding materials involves the presence of Mg-rich phase within Baroque mortars as a result of carbonation of a dolomitic lime whereas Gothic mortars are devoid of hydromagnesite. Mineral composition of the fillers of both mortars is similar, suggesting the same origin represented by local eluvium. Binders of studied mortars are composed of calcite and/or hydromagnesite and rich in lime lumps suggesting incomplete calcination. Studied mortars are weathered which is manifested by presence of gypsum. However, there is no evidence of commonly occurring Mg-rich secondary phases within Baroque mortar probably due to higher solubility of these salts comparing to gypsum. Mineralogical study combined with archeological and geological information enables us to indicate potential sources for the studied building materials. Metamorphic rocks, prevailing within the façade, come from abandoned quarries located in the closest vicinity of the church, whereas sandstones were acquired from the deposits located at a distance of tens of kilometers from the Kamieniec Z?bkowicki. Raw materials used for lime burning were gathered from Przeworno (Gothic mortars) and Z?oty Stok area (Baroque mortars) located approximately 25–30 and 12 km from studied church.     

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.     

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.     

The ancient pozzolanic mortars and concretes of <Emphasis Type="Italic">Heliocaminus</Emphasis> baths in Hadrian’s Villa (Tivoli,Italy)

The aim of this work is the physical and mineralogical-petrographic characterization of the mortars from the Baths with Heliocaminus, a special and unique architectural building in the complex of the Hadrian’s Villa in Tivoli. Thirty samples were investigated for composition and physical properties (density, porosity, water absorption, mechanical strength, particle size distribution of aggregate, etc.), representative of eight mortar groups: cubilia bedding mortar, brick bedding mortars, floor-coating and wall-coating bedding mortars, floor (rudus) and wall conglomerates (trullisatio), vault concretes, and lime plasters (arriccio). Physical parameters, together with the microscopic analysis and binder/aggregate ratio determined in three ways using image analysis (on thin sections and on specimens) and weight-data from dissolution of binder, have shown an interesting relationship between the physical-compositional characteristics and the function of mortars within the structure of the Heliocaminus baths. To identify the minerals and the reactant phases between binder and aggregate, as well as the hydraulic degree, selected samples were analyzed with x-ray powder diffraction, thermogravimetry, and differential scanning calorimetry techniques. The obtained results provide a close relation between pozzolanic characteristics and physical-mechanical properties of the mortars (i.e., punching strength index).     

Historical mortars dating from OSL signals of fine grain fraction enriched in quartz

In the last years the mortar dating through Optically Stimulated Luminescence (OSL) techniques has become a viable support for chronological estimations (date of construction or restoration episodes) of historical buildings. However, the dating of mortar has still open issues mainly regarding the assessment of the bleaching degree of quartz, the analysis of the OSL processes for this type of samples and the need to do appropriate tests for the most correct evaluation of the equivalent dose. This paper discusses the results obtained by OSL dating (blue diode stimulation) on the polymineral fine grain phase, enriched in quartz, extracted from lime mortar samples collected from different sites. Thermal transfer effects, through the behaviour of Equivalent Dose (ED) and recovery tests, degree and time of bleaching were studied. For each mortar sample the adjacent brick was collected; in some cases, sampling of the bricks bracketing a mortar layer was a possibility, thus obtaining a direct comparison with the standard thermoluminescence (TL) dating on the bricks. The results obtained show, for this set of samples, the possibility of dating the mortars through the use of the fine grain fraction provided of a suitable chemical-physical preparation procedure and the verification of the bleaching conditions.     

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.     

Comparison of Original and Modern Mortars at the Herculaneum Archaeological Site

ABSTRACT

This paper aims to evaluate mineralogical, elemental, and thermal differences among original Roman joint mortars and those used in twentieth-century restoration campaigns taken from different areas at the Herculaneum archaeological site. The purpose is to improve the compatibility of restoration mortars. Roman and modern mortars were studied with petrography, thermal analysis and x-ray fluorescence investigations. The results indicate significant differences between the Roman and modern mortars which could facilitate the degradation process. Roman mortars, in particular, were composed of a coarser aggregate which was present in a lower ratio with binder in comparison with modern mortars.     

Paper 5: Historic Mortars from the Coudenberg Archaeological Site: Characterization and Source of Raw Materials

Abstract

The characterization of historic mortars by means of a concise methodology of material analyses can provide crucial information with regard to the origin of the raw materials and the ancient mortar technology. For the analysis of the historic mortars of the Coudenberg archaeological site, the methodology consists of optical and scanning electron microscopy, simultaneous thermal analysis, and an acidic treatment. These analyses were carried out on a total of seventeen samples lifted from various areas in the site, in function of the building chronology resulting from a historic built investigation. The type of binder and aggregate as well as their volumetric ratio were determined.

Both binder and aggregate present distinctive features, which made it possible to identify the probable geological provenance of the raw materials. The observations are verified with available historical records regarding the construction of the main banqueting hall — the Aula Magna — and the use of raw materials such as limestone and sand for the production of lime and construction purposes.     

故宫博物院旧藏漆器文物中漆灰材质的科学研究

漆灰的修复是漆器文物修复工作的重要组成部分。为揭示故宫博物院旧藏漆器3种典型漆灰的材料构成及特点,以及为漆器修复工作提供科技支持,研究结合X射线荧光光谱、微区X射线衍射、红外光谱、纤维显微镜观测、热裂解-气相色谱/质谱联用等技术,综合分析了3种典型漆灰所含无机及有机原材料。研究结果表明：明代古梅花蕉叶式琴漆灰所用无机材料是动物角灰或骨灰及少量黏土,胶结材料则由中国大漆及少量植物油组成;清代黑漆描金大宝座漆灰的无机材料为含有方解石的黏土,胶结材料为熟桐油、猪血的混合物,此外,样品中还含有麻类纤维,为宝座木胎与漆灰层之间所裱麻布,宝座漆灰不但能提供平整髹漆表面,而且还对麻布有加固定型作用;清代黑漆地填金字张廷玉书圣训天伦对联漆灰的无机材料为黏土,胶结材料则为熟桐油、猪血的混合物。研究所用分析方法体系可实现漆灰原材料,特别是有机胶结材料的准确识别。3种典型漆灰的选材特点与中国古代漆器,特别是明清时期家具、器物制作用料传统相吻合,研究结果可直接应用于漆器文物修复方案的制定。     

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.     

EVALUATION OF INCLUSIONS IN MORTARS OF DIFFERENT HISTORICAL PERIODS FROM GREEK MONUMENTS*

Mortars were among the first materials used for construction purposes, even from prehistoric times. Their systematic study reveals that they often contained inclusions, which were introduced with the main constituents or added as improvers of mortars' properties. The present study focuses on recording the types of inclusions found in more than 1000 mortar samples of different types (structural, renders and floor mosaic substrates), taken from various monuments of Greece. This extensive study proves that inclusions occur in all types of mortars of all periods and can be distinguished into two categories: those that are added deliberately to mortars to meet specific needs of improvement of their final properties, such as fibrous materials (wood chips, straw); and inclusions that are incorporated into the mass as impurities in the raw materials (lime and clay lumps, shells and probably charcoal particles).