明《天工开物》之“风吹成粉”工法初步研究

Preliminary study of lime slaked by wind according to the book,Heavenly Creations( Chinese Technology in the Seventeenth Century)

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。

Heavenly Creations（ Chinese Technology in the Seventeenth Century）,by SONG Ying-xing,was published in 1637 during the Ming Dynasty. The book recorded the ancient slaking technique,i. e.,＂quicklime was exposed to wind and became a powder after long blowing; the lime was sieved and mixed with water to make mortar for masonry＂. In order to understand the properties of the lime slaked by wind or air,we studied quicklime with three types of slaking methods. The quicklime was supplied by a conventional high calcium lime production company,which mines the limestone near the border between Zhejiang and Anhui. The limestone was calcined in classical shaft kiln using coal. The quicklime was slaked by three methods： wind,mist spray and water bath. Mineralogical studies show the calcium silicate minerals,such as belite,have been found in both quicklime and limes slaked by wind and mist. The lime slaked by wind has a higher strength but shorter setting time. Its compressive strength can reach 1. 5 Mpa in 28 days. The preliminary results show that the performance of lime blown by wind is equivalent to NHL1 or NHL2 of EN 459-3（ 2015） but has faster setting characteristics. Fast setting can not only shorten construction time but also be very conducive to the applications in humid and cold climates. Both literature and remains/ruins of the Ming Dynasty and earlier constructions should be further studied in order to revitalize the use of this traditional ecological and inorganic material fused with ancient Chinese wisdom for conservation of cultural relics.