Study of Frost Weathering Mechanism of Porous Materials and its Protective Measures.

1)寒冷地区的砖砌建筑和石碑由于冻融循环而退化。通过对北海道旭川会馆砖烟囱和福岛县盐津砖烟囱冻害的现场调查，发现供水是造成冻害的重要因素。提出了计算砖建筑和石碑中含水量分布和水流的数值方法，该方法同样适用于干旱地区砖建筑和石碑中与盐风化有关的水分和溶质运移的计算。2）冻土风化的基本机理是冻胀现象。在多孔材料的冻结过程中，水被诱导流动到冻结前沿并作为透镜分离。为了阐明玻璃微珠的冻胀机理，采用不同粒径的玻璃微珠进行了不同温度条件下的冻胀试验。实验结果给出了 ...更多信息 并与基于晶体生长理论的冻胀模型进行了比较。这些结果在国际研讨会上发表并发表在期刊上。3）当冻胀压力超过其拉伸强度时，石质纪念碑的多孔材料，如Oya凝灰岩破裂。利用显微镜和摄像系统对不同温度条件下的冰分凝过程进行了实验研究。提出了该过程的冻胀模型，并与试验结果进行了比较。计算结果与实验结果吻合较好。4）在大分县的石碑上观察到盐风化现象。盐风化是由于水分从地表蒸发时，在近地表处发生盐结晶过程而引起的。这一物理过程类似于霜冻风化过程，物质运移可用类似的微分方程表示。由于这些相似之处，我想扩大我的研究课题有关霜冻风化盐风化，可以看到在亚洲国家的历史遗迹。少

1) The brick buildings and stone monuments in cold regions deteriorate due to freezing and melting cycles. The field survey on the frost damages of brick chimney of Asahikawa Kaiko-sha in Hokkaido Prefecture and brick chimney of Ynaizu in Fukushima Prefecture revealed that the water supply was important factor for frost damage. The numerical technique to calculate water content distribution and water flow in brick buildings and stone monuments was developed, This technique is also applicable to the calculation of the water and solute transport related to salt weathering in the brick monuments in dry regions.2) The basic mechanism of frost weathering is frost heave phenomenon. During the freezing of porous material, water is induced to flow to the freezing front and segregates as lenses. In order to clarify the frost heave mechanism, frost heaving experiments were performed using glass beads of different diameter under different temperature conditions. The experimental results gave the … More relationship between the ice segregation rates and temperature conditions, The experimental results were compared with the frost heave model based on the crystal growth theory. These results were reported in the International Symposium and published in journals.3) The porous materials of stone monuments , such as Oya tuff break when the frost heave pressure exceeds their tensile strength. The laboratory experiments were carried out to investigate the ice segregation process under the different temperature conditions by using microscope and video recorder system. The frost heave model for this process was proposed and compared with the experimental results. The calculated results corresponded well with the experimental results. These results were presented at the International Symposium.4) The salt weathering is observed for stone monuments in Oita Prefecture. The salt weathering is caused by the salt crystallization process near the surface during the water evaporates from the surface. This physical process is similar to the frost weathering, The material transport is expressed by similar differential equations. Because of these similarities, I would like to widen my study topic related to frost weathering to salt weathering which can be seen in historical sites in Asian countries. Less