明砖石长城保护维修关键石灰技术研究

2019年1月发布的《长城保护总体规划》提出以“整体保护”为思路的“原址保护、原状保护”总体策略，实现此策略的难题之一是落后的石灰技术，体现在缺乏系统针对以明长城为代表的长城建造时采用的石灰烧制、储运、配方与工法的研究，缺乏长城病害机理特别是在现代环境下的石灰耐久性研究，缺乏实现总体策略的石灰材料技术体系研究。本课题将剖析文献，考察长城沿线的石灰窑址，调研明代代表性砖石长城灰浆遗存及相关原始建造工艺，记录病状，在阐明病害机理基础上明确长城保护维修需要的石灰材料体系。利用现代材料学等研究方法分析不同地区具有代表性的明长城灰浆样品，定量确定长城建造用灰浆类型，回答明代石灰“为什么强度高”、 “修长城需要什么石灰“等基本问题。开展模拟煅烧与消解等实验，阐明以长城建造为代表的明代传统灰作技术体系。同时开发出适合抢救性保护的理化性能与长城本体兼容的灌浆和维修等石灰材料，为长城保护提供基础性技术支撑。

"Conservation master plan of the Great Wall " released in January 2019 proposed two conservation principles as the overall strategy: "in situ conservation” and “conservation of the original status”. One of the challenges to achieve this strategy is lime technology. There is lack of systematic researches on traditional kilning, slaking and storage, formulation and installation technique to construct the Great Wal. There is also lack of researches on defects especially the defects caused by modern polluted environment. Thirdly no systematic lime material solutions have been worked out. Therefore, the proposed research project will deepen the literature research combined with examination of the archaeological sites of the lime kiln along the Great Wall. The project will also investigate the construction technique and defects. Based on the analysis of the representative samples of the Great Wall mortars in different regions by means of modern material sciences and options of conservation solutions, the research team will clarify following fundamental questions, whether the high strength of old mortars is related to "dolomitic lime", what kinds of lime materials are compatible for conservation and maintenance. Experiments such as simulated calcination and slaking (wet and dry slaking) are carried out to elucidate the traditional lime technology system of the Ming Dynasty represented by the Great Wall. At the same time, compatible grouting and maintenance lime materials with optimized physical and chemical properties suitable for rescue restoration and conservation the Great Wall will be also developed to provide basic technical support for the conservation of the Great Wall.