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。     

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。     

新型土遗址修复加固材料试验研究

考虑到土遗址夯筑本体水敏性和稳定性较差的特性,以及长期受自然因素营力作用的影响,采取科学的修复材料补夯的措施可有效抑制土遗址本体残损的进一步发展。以河南地区典型粉砂土为研究对象,制备不同配比石灰-偏高岭土改良材料,研究其对基准土样强度性能的影响和微观机制,并对比分析水硬性石灰土。结果表明:对比NHL,综合考虑石灰-偏高岭土对基准土样击实特性、无侧限抗压强度和强度增长率的影响,采用6﹪-8﹪石灰+4﹪偏高岭土改良粉砂土,在强度特性方面达到了水硬性石灰的修复性能,实现了对粉砂土更好的改良效果。结合SEM发现,掺入偏高岭土后生成的水化产物,可联结土体颗粒、充填空隙,使改良土微观结构更加致密。     

用于古建筑琉璃瓦保护的高分子聚合物材料的分析研究

为探索高分子聚合物用于古建筑琉璃瓦的保护研究,采用所选择的9种有机高分子聚合物对现代黄釉琉璃瓦进行保护处理,分析保护材料的耐光性能及保护后琉璃瓦的憎水性、耐冻融性和化学稳定性等性能,同时选择性能较好的材料用于胎体酥粉古琉璃瓦的保护,分析憎水性、耐冻融性、耐折、抗压强度、透气性以及进行保护机理研究.结果表明,保护材料丙烯酸类材料的Primal SF和1372耐光性能较差;用于现代琉璃瓦保护的Primal SF憎水性和耐冻融性较差;有机硅的耐酸碱性较差;聚氨酯和硅丙乳液的憎水性和耐碱性能较差;氟碳清漆、氟树脂和复配材料的各项性能相对较好;含氟聚合物及其氟树脂为主的复配材料用于胎体酥粉古琉璃瓦保护的憎水性、耐冻融性、耐折、抗压强度和透气性等性能相对较好,保护材料以良好的渗透能力渗入古琉璃胎体内部,有效提高胎体强度,起到填充空隙和防止水分破坏的作用.综合几项指标,含氟聚合物及其复配材料的各种性能优良,为选择中国古建筑琉璃瓦的保护材料提供科学依据.     

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。     

明《天工开物》之“风吹成粉”工法初步研究

1637年(明崇祯十年)出版的《天工开物》记录了我国古代建筑石灰的消解采用"置于风中,久自吹化成粉"的工艺,"用以砌墙石,则筛去石块,水调黏合"。为复配"风吹成粉"工法并研究采用这种工法得到的石灰性能,实验采用传统立窑对源自浙-皖交界处原材料"青石"烧制而成的生石灰使用"风吹法"消解,并参照现代标准BS-EN-459-2015等相关检测方法进行性能研究。结果发现"风吹法"消解的石灰含有水硬性组分如硅酸二钙等,并具有凝结时间短、强度适中等特点。研究表明,"风吹"20~30天左右得到的石灰性能相当于欧洲标准的天然水硬石灰NHL1或NHL2。研究还表明,"风吹成粉"的石灰可以用作砌筑、修复、注浆等粘合剂,其快凝等特性非常有利于湿冷环境下的施工。若对文献、明及以前的建筑进一步考证并采取系统全面的深化研究,有望考证出我国380年前的明朝对天然水硬石灰消解及应用技术的掌握程度,并开发出融合中华传统智慧的文物建筑保护材料。     

贺兰口岩画风化病害机理

贺兰山岩画在世界岩画中占有重要的地位,由于自然环境因素的长期作用,贺兰山岩画遭受到了严重的破坏,若不尽快采取有效措施,这些珍贵的历史文物将不复存在。但是,截至目前关于贺兰山岩画风化机理的研究甚少,从而严重制约了对其风化机理准确地、有效地科学认识。为此,以贺兰口岩画为研究对象,在风化现状调查的基础上,对其保存环境的温度、湿度、大风及沙尘天气等数据进行统计分析,利用X射线衍射仪、扫描电子显微镜等测试手段,并结合冻融实验和风洞试验进行风化病害机理研究。研究发现,贺兰口岩画以长石杂砂岩为主,引起其风化的因素有温度、湿度、风沙等。其中,温度变化和风沙剥蚀为主要病害因素。该研究有望为全面了解岩画风化机理以及其后续保护工作的实施提供理论基础。     

贺兰口岩画风化病害机理

贺兰山岩画在世界岩画中占有重要的地位,由于自然环境因素的长期作用,贺兰山岩画遭受到了严重的破坏,若不尽快采取有效措施,这些珍贵的历史文物将不复存在。但是,截至目前关于贺兰山岩画风化机理的研究甚少,从而严重制约了对其风化机理准确地、有效地科学认识。为此,以贺兰口岩画为研究对象,在风化现状调查的基础上,对其保存环境的温度、湿度、大风及沙尘天气等数据进行统计分析,利用X射线衍射仪、扫描电子显微镜等测试手段,并结合冻融实验和风洞试验进行风化病害机理研究。研究发现,贺兰口岩画以长石杂砂岩为主,引起其风化的因素有温度、湿度、风沙等。其中,温度变化和风沙剥蚀为主要病害因素。该研究有望为全面了解岩画风化机理以及其后续保护工作的实施提供理论基础。     

壳聚糖/二氧化硅复合仿生膜对 碳酸盐石材的保护作用

为探讨壳聚糖/二氧化硅复合仿生膜对碳酸盐石材的保护作用,采用仿生合成技术,以十六烷基三甲基溴化铵为有机模板,能过壳聚糖调控二氧化硅颗粒的生长,在碳酸盐石材表面仿生合成得到了一层壳聚糖/二氧化硅复合保护膜,对其基本性能进行了检测评价,并利用衰减全反射红外光谱和场发射环境扫描电子显微镜表征了膜的结构形貌。实验结果表明,该膜具有优良的耐酸、耐污性能,提高了膜层的抗冻融性和耐热老化性能,并保留了石材原有的吸水性和透气性。壳聚糖/二氧化硅复合膜改善了单一二氧化硅膜的开裂问题,且该保护膜与石材基体结合紧密、膜层薄,小影响石材外脱,是一种良好的碳酸盐石材保护材料。     

桐油与石灰加固吉野里坟丘墓土的实验研究

用夯筑方法建造的土遗址在公开展示之前需要对土遗址的本体进行修复和加固。通常采用合成树脂作为土遗址本体和表面处理的材料,但合成树脂作为加固材料存在着一系列的问题,如会降低土体强度及对构造造成破坏。本工作针对日本九州地区广泛分布的真砂土和火山灰土为材料修筑的土遗址修复工程,尝试运用石灰、糯米汁、桐油作为土遗址的修复材料。按照不同的配合比制作试验土样进行无侧限抗压、固结、干湿循环、冻融循环等试验。结果显示,添加了4％桐油和石灰的土样能够大幅度提高夯土的强度,且压缩性低、抗冻融性好,尤其能显著提高土样的抗干湿劣化的性能。建议在九州地区的土遗址修复和保护工程中运用。     

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。     

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.     

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。     

冻融作用对古青砖宏观性能及微观结构劣化的影响

砖质文物建筑多数处于室外工作环境,其损伤呈现出冻融循环条件下的物理风化和材料水解条件下的化学风化联合作用破坏形态,致使古青砖文物面临着严重的环境侵蚀风化问题。为此,以古建筑青砖为研究对象,通过对6组试样分别进行0,15,30,45,60和75次冻融循环试验,分析冻融循环次数对古青砖的孔洞率、质量、抗压强度的影响规律。在此基础上,通过TEM(透射电子显微镜)扫描探讨了冻融作用对古青砖微观结构的损伤过程及劣化机理。结果表明:随着冻融循环次数的增加,古青砖的孔洞率、质量损失率以及强度损失率均增大;TEM扫描发现冻融对古青砖造成了明显的微观孔隙结构损伤,特别是75次冻融循环后该损伤明显激增。同时,利用XPS(X射线光电子能谱仪)测试古青砖化学成分的组成,说明青砖体内碳酸盐等可溶性盐类的晶体水解造成青砖的微观孔隙结构损伤,是其遭受化学风化作用的主要原因。     

Digital imaging technology and experimental archeology: a methodological framework for the identification and interpretation of fire modified rock (FMR)

This paper presents the results of a series of experiments for the identification and analysis of fire modified rock (FMR). FMR is a common but frequently overlooked artifact type. Experiments were conducted simulating the effects of different hypothetical burning scenarios on rocks similar to those found in a South African Middle Stone Age site. A digital imaging method was then used to quantify FMR color values, designed to limit intra-analyst bias. Statistical tests and a blind test suggest that unburned rocks and experimental FMR can be separated statistically based on physical appearance. Two burning scenario models, based on measured experimental data were applied to archaeological FMR from a South African Middle Stone Age site named Pinnacle Point 5-6 (PP5-6) and show that the archaeological samples are not statistically different from a simulated campfire and possibly a lithic raw material heat-treatment fire.     

Paper 6: Grouting Mortars for Fragmented Bricks and Repair Mortars for Tiles in the Archaeological Site Coudenberg

Abstract

Different grouting and repair mortars were developed and evaluated for the conservation and restoration of fragmented bricks in the walls and floors of the remaining cellars underneath the Aula Magna, the palace’s main banqueting hall, and to fill the lacunae and perform edge repairs of red and blue-grey ceramic floor tiles in the remaining cellars underneath the chapel of the former Palace of Coudenberg in Brussels, Belgium.

To prevent the deposition of lime bloom at the surface of the masonry and to achieve an acceptable colour match of the grout in harmony with the bricks of the Aula Magna, the effect of brick powder added to natural hydraulic lime was studied. The pozzolanic properties and colour match of several historic and modern powdered bricks were investigated. Surprisingly, ancient bricks do not seem to possess higher pozzolanic properties than the more modern ones, although it is supposed that they were fired at lower temperatures. Additional evidence for the pozzolanic reaction of the different brick powder materials was obtained from a simple visual observation of stored samples. After eight weeks all of the samples containing brick powders, fired at low and high temperatures, added to putty lime had hardened under water and were transformed into a remarkably tough material. These results are important, as modern bricks are readily available in large quantities and different colours, which are hence in favour of being used instead of historical material from the site.

For the repair of the ceramic floor tiles different mortars were investigated with mixtures containing talcum, stone or brick powder, pigments, and chalk added to an epoxy binder. The mortars were tested in the laboratory and in situ for their workability and resemblance with the historic floor tiles. The finished mortars showed excellent aesthetic properties with the tiles in situ and good properties to prevent further loss due to human interaction.     

Site conservation during excavation: treatment of masonry,wall plaster and floor mosaic remains of a Byzantine church in Petra,Jordan

Abstract

The conservation treatments carried out between June 1992 and August 1993 on the architectural remains of a Byzantine basilica in Petra, Jordan, during and immediately after the excavation are described. The treatments completed during excavation included: stabilization and consolidation of certain sections of the basilica's sandstone ashlar masonry; cleaning and consolidation of the unpainted lime wall plaster decorating the basilica interior; cleaning and consolidation in situ of the extensive remains of a figurative mosaic pavement in the two side aisles, and the fragmentary remains of the opus sectile pavement in the central aisle. The consolidation treatments included injection grouting using hydraulic mortar mixes produced in Italy, and mortar repairs using slaked lime and hydraulic lime. The existence of the mosaic required preventive conservation measures during the excavation, such as the construction of a temporary shelter over the site during the winter, the use of temporary protective facings over damaged areas of the mosaic, as well as the temporary backfilling of the mosaic with soil over a layer of geotextile in order to protect the mosaic between the initial phase of conservation work and the construction of a permanent shelter for the site in the near future. The importance of having a conservator present on site during the critical phase of excavation, when all materials are most susceptible to damage, is emphasized. The Petra Church Project will hopefully serve as a model for future excavations in that it employed two conservators from the beginning of the excavation: one for small finds, the other responsible for the site and the architectural remains removed from the site during the excavation.