海上丝绸之路窑址裂隙充填灌浆材料比选室内试验研究

对裂隙进行充填灌浆,可以有效防止裂隙的进一步发展和雨水的渗漏,使遗址得以更好地保存。为比选出适宜于潮湿环境下窑址裂隙充填灌浆材料,采用烧料礓石、烧阿嘎土、砺灰三种传统石灰材料分别对浙江和福建四处"海上丝绸之路"遗址点的遗址土进行改性研究。测试改性后浆体材料不同龄期的抗压、抗折强度、收缩率,以及温湿度循环、冻融循环、水稳定性、安定性、耐碱性试验后试样的力学性能变化。试验结果表明,三种石灰类材料均具有良好的耐候性,但砺灰试样的耐冻融特性稍差、龄期强度低、收缩变形较大。烧料礓石改性试样具有较高的龄期强度、较低的收缩率、良好的耐候性。因此,建议将烧料礓石作为主剂应用于四处窑址的灌浆材料中。相关研究成果对窑址裂隙灌浆材料的选取具有实际指导意义。     

Combined In-Situ and Laboratory Minor Destructive Testing of Historical Mortars

ABSTRACT

Mortar is of all masonry components the most difficult to be experimentally characterized in heritage buildings. This article investigates the possibility of combining different in-situ and laboratory minor destructive testing (MDT) techniques to assess the strength of mortar in historical brickwork. Lime mortar and clay brick walls were built in the laboratory and then tested in order to derive empirical correlation rules among three different MDT techniques: double punch test (DPT), helix pull-out test (HPT), and pin penetration test (PPT). The outcomes of this activity were used eventually to assess the mortar properties of an important historical heritage structure, Casa Puig i Cadafalch, located near Barcelona. The research is intended to promote the use of MDT in studies and conservation works on built cultural heritage by providing criteria for the evaluation of the strength of existing mortar with respectful sampling and testing techniques.     

Lime Powder Production in the Maya Puuc Region (A.D. 600–950): An Experimental Pit-Kiln

Powdered lime was one of the most significant materials in the daily lives of the Prehispanic Maya, yet archaeologists have uncovered relatively little evidence of production methods or locales prior to the Spanish conquest. The recent identification of a series of pit-kilns dating to the Late and Terminal Classic periods (ca. a.d. 650–950) in and around the site of Kiuic in the Puuc region of the northern lowlands of the Yucatán Peninsula provides the opportunity to investigate a sub-regional Prehispanic lime production technology. Here we present the preliminary excavation results of nine pit-kilns and then describe the experimental reconstruction and firing of a lime pit-kiln. The results indicate that the pit-kilns are more fuel-efficient than the aboveground pyres used during the post-conquest period. This in turn suggests that Prehispanic inhabitants of the Puuc managed their consumption of natural resources for producing lime during a period of sociopolitical, demographic, and environmental stresses.     

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.     

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.     

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.     

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.     

Investigation and analysis of ancient brick carvings of the Liuhe Pagoda in Hangzhou

The Liuhe Pagoda in Hangzhou, China, has a large number of brick carvings from the Southern Song Dynasty (1152 ce ), covering an area of 464 m². However, the exquisite brick carvings in the Liuhe Pagoda have deteriorated due to natural weathering and a high-humidity environment. Through laboratory analysis and on-site nondestructive testing, the physical and chemical properties of the brick carvings of Liuhe Pagoda were investigated, and the weathering mechanism of the brick carvings was further analyzed. The brick carving of Liuhe Pagoda is composed of brick, white plastering and black coating. CaCO₃ is the main component in white plastering, and the black coating on the top surface contains Chinese lacquer. The weathering products of the brick were analyzed and a trace of CaSO₄.2H₂O was found. In addition, the brick carvings with high water content have low Leeb hardness and severe weathering. Therefore, water and soluble salt are the main factors in weathering of the brick carvings of the Liuhe Pagoda.     

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。