Preliminary Study On Lime-soil In Ancient Rammed Earth Construction Site In China

Rammed earth buildings belong to the scope of earth buildings which had extensive applications and distributions in ancient China.The construction of ancient rammed earth building, including the selection of building environment, screening and processing of building materials, and improvement of construction technique,implies the profound wisdom of our ancestors. Lime soil was already used at China’s late New Stone Age, and later with the continuous improvement of lime production technique, was gradually widely used on construction, both as cement and rammed earth. Based on previous investigation, this paper mainly covers the following aspects through taken basic soil test and some modern analysis technology:1. X-ray diffraction and scanning electron microscopy were used for qualitative and quantitative analysis. It is found that Tongwancheng rammed earth sample has lime with12.5%calcite, so as to imperial city of Liao Shangjing, with33.8%calcite, which is similar to3-7lime soil but sample from Hancheng of Liao Shangjing does not have lime; the calcite percentage of sea plaster layer from Ming Dynasty Great Wall, which is made of lime and clay, is up to70.3%; Ming Dynasty rammed earth sample1has no lime and rammed earth sample2has11.6%calcite; rammed earth sample from Baiyanggou has41.8%calcite while no lime is found in the adobe there. In addition, scanning electron microscopy analysis indicates that rammed earth with lime is of more compact structure and soil particles bonding.2. Physical and chemical characteristics tests of rammed earth have been carried out to Tongwancheng site, Liao Shangjing site, Ming Dynasty Great Wall at Yulin, Shaanxi Province and Buddhist Temple site at Baiyanggou, Hami. The results show that rammed earth from Tongwancheng site possesses good physical and chemical properties, especially its mechanical strength which is above average level in China; the physical and chemical properties of imperial city of Liao Shangjing site are better than that of Hancheng; the physical and chemical properties of sea plaster layer from Ming Dynasty Great Wall are the best of the three samples and the other two are nearly same, with sample2slighter better; the physical and chemical properties of Baiyanggou site is better than adobe.3. Iodine starch color reaction tests were done to find out if there is glutinous rice ingredient in the samples from above mentioned sites. Results of all iodine starch color reaction tests were light yellow which means that samples do not contain organic components of sticky rice.In summary, taking lime soil of typical rammed earth building sites as examples, this paper analyzes their components, structures and physical and chemical properties, acquiring certain achievements to the study on traditional lime-soil material.