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。

Preliminary research on traditional dolomitic lime in ancient Chinese architecture

According to the analysis of chemical and mineral components of building mortars from the Ming Dynasty to the Republic of China, some masonry and plastering mortar is dolomitic lime or magnesium lime, and the content of MgO ranges from 5% to 26%. In particular, all mortar samples from the Great Wall belong to dolomitic lime. Compared with calcium lime, dolomitic lime boasts higher strength, lower water absorption, lower shrinkage and better workability; therefore it is more frost-resistant than calcium lime. In addition, the temperature and energy required for calcining dolomitic lime is lower than that required for high-calcium lime. It is recommended that further research on dolomitic lime be carried out systematically in China, and that it includes the type and distribution of raw material, calcination temperature, slaking, optimal formulation and technologies for restoration, etc. At the same time, it is suggested that further research also be carried out on the durability of dolomitic lime under atmospheric industrial pollution, as well as the conservation and restoration technologies for dolomitic lime-related architectural heritages.