汉中山河堰二堰和羊头堰灰浆的分析研究

Analysis of Mortar Composition of Shanhe Weir and Yangtou Weir in Hanzhong City

陕西汉中三堰(山河堰、五门堰、杨填堰)在2017年10月被确认成功申报世界灌溉工程遗产并授牌,其中山河堰是汉中地区最早的灌溉工程。20世纪80年代,在水文考古普查时发现,山河堰砌体以木桩砌石为骨架,使用可能加入桐油、糯米浆的黄泥、沙、石灰搅拌而成的三合土作为填充物。为深入探究山河堰灰浆的成分和科学机理,对山河堰的灰浆样品进行了成分分析,并检测了样品的年代信息。该研究在山河堰二堰东堤和羊头堰取样,利用X射线衍射分析(XRD)、傅里叶变换红外光谱分析(FTIR)、差热分析、扫描电镜、岩相等科技手段,检测分析样品的组成成分。另外,利用碳-14检测对山河堰二堰灰浆进行断代分析。分析结果表明,山河堰二堰东堤石条粘合物经年轮校正后的年代为公元1150年—1226年(南宋时期),山河堰二堰东堤粘合物和夯土以及羊头堰粘合物的无机成分主要为方解石、石英及少量长石。其中,粘合物中石灰的添加量较高,夯土中石灰的添加量较低。红外分析和热分析结果表明,粘合物和夯土中似乎添加了某种有机物,结合文献资料分析该有机物很有可能为糯米浆。热分析结果显示,800℃以上出现的放热峰为水化硅酸钙的特征峰,推测石灰与水发生反应生成水化硅酸钙。水化硅酸钙能在水中或潮湿的环境中更好地硬化,它是水利工程可以保存数千年的主要原因。电镜检测结果显示,样品中尚未被碳化的消石灰(Ca(OH)2)脱水形成羟钙石晶体。另外,灰浆中加入的有机物和灰浆的缓慢碳化都有助于增强灰浆砌体的自我修复能力和抗风化能力,延长水利工程的使用期限。采用各种科学手段对山河堰灰浆进行科学研究,有助于探明水利工程灰浆材料的组成及其科学机理,为山河堰等水利工程遗产的保护修缮奠定科学基础,并可为现代水利工程材料的改良提升提供有益的启示。

Three weirs(Shanhe weir,Wumen weir and Yangtian weir)in Hanzhong city,Shaanxi province was successfully listed in the world irrigation engineering heritage list in October 2017.Among them,Shanhe weir is the earliest irrigation project in Hanzhong region.During the hydrological archeological surveyin the 1980s,it was found that the Shanheyan masonry was made of wooden stake masonry as a skeleton and tri-soil composed of yellow mud,sand,lime,Tung oil and glutinous rice pulpas the filler material.In this study,mortar samples from the east embankment and Yangtou weir of Shanhe weir were detected by X-ray diffraction analysis(XRD),fourier transform infrared spectrometry(FTIR),thermal analysis,scanning electron microscopy,petrographic analysisand 14 C dating technology to determine the date,composition and scientific mechanism.The result of 14 C dating of the stone strips of the East dike ofShanheweir was that they could date back to 1150 to 1226 AD,which indicated that the date of Shanhe weir could be be date back to the Southern Song Dynasty.Based on the results of XRD and FTIR,the inorganic components of the East dike and rammed earth and Yangtouweir were mainly calcite,quartz and a small amount of feldspar.Infrared analysis(FTIR)and thermal analysis showed that some organic matter appears to be added to the clay and rammed earth.Combined with the literature,the organic matter was likely to be glutinous rice pulp.The heat analysis results showed that the exothermic peak above 800℃was the characteristic peak of calcium silicate hydrate,and it was assumed that lime reacts with water to produce calcium silicate.Calcium silicate can harden better in water or in moist environments.It is the main reason why water Conservancy projects can be preserved for thousands of years.The results of electron microscopy showed that the non-carbonized decalcitrate(Ca(OH)2)in the sample was dehydrated to form a hydroxycalcite crystal.In addition,the organic matter added to the mortar and the slow carbonization of the mortar are helpful to enhance the self-repair ability and weathering ability of the mortar masonry and extend the service life of the water Conservancy project.This work uses various natural science means to carry out scientific research on the ash pulp ofShanhe Weir mortar,which is helpful to find out the composition and scientific mechanism of the mortar material of water Conservancy project,lay a scientific foundation for the protection and repair of water Conservancy project heritage such as Shanhe Weir,and provide useful enlightenment for the improvement and enhancement of modern water Conservancy materials.