The Establishment of Evaluation Technique of Long Term Preservation of Cultural Heritage Brick Buildings

最近，明治时代和大正时代的砖房的历史价值得到了认可，被指定为文化遗产的建筑也在增加。为了使砖石建筑保持良好的保存状态，必须收集构成砖石建筑的砖和接缝的基本数据，以及由砖和接缝组成的砌体结构的物理性能。在本研究中，研究了各种砖建筑中使用的砖的物理性能。根据调查结果，对砖瓦建筑长期保存的修复方法进行了评价。为了获得砖的物理性质的基本数据，用于评估砖建筑长期保存的可能性，我们对日本各地收集的砖进行了调查。因此，人们发现砖的各种物理性质会随着时间的流逝而发生变化。即反复干湿作用导致抗压强度和杨氏模量降低，冻融阻力增大，孔隙率减小，应变增大。此外，将超声波脉冲速度估计的杨氏模量与以往研究中得到的各种物理性质进行比较，虽然很难发现砖的各种物理性质之间存在明确的关系，但可以清楚地看出，增强砖的抗压强度和降低砖的毛细管和运动对长期保存是有效的。对砖墙未填缝处注入修补材料的修复方法进行了研究，这是砖墙建筑保护中普遍采用的方法。为了研究该方法对砖瓦动态性能的改善效果，给出了几种砖瓦材料和接缝部位修补材料的配合比。此外，采用由砖和接缝组成的砖砌体结构，在接缝处注入各种修补材料，进行无侧限压缩试验和箱形剪切试验。结果表明，砌体结构材料之间在断裂过程中的差异，以及注入修复材料对砌体结构强度的显著提高。少

Recently, the historical value of brick buildings built during the Meiji and Taisho Eras has been recognized, and the number of buildings designated as cultural properties has increased. In order to keep the brick buildings in a good state of preservation, basic data on brick and the jointing which compose the brick buildings as well as the physical properties of the masonry structure consisting of the brick and the jointing must be collected. In this study, physical properties of bricks used in various brick buildings were investigated. Based on the results of the investigation, methods of repair for the brick buildings' long-term preservation were evaluated.In order to obtain basic data on the physical properties of bricks, which are used for evaluating the possibility of the brick buildings' long-term preservation, bricks collected in various places in Japan were investigated. Consequently, it was found that various physical properties of the bricks changed according to the passage … More of time. Namely, the compressive strength and the Young's modulus decreased, the freeze-thaw resistance increased, the porosity decreased and the strain increased due to repeated dryness and moisture. Moreover, when the Young's modulus estimated from the ultrasonic pulse velocity was compared with various physical properties obtained in previous studies, although a clear relationship among the various physical properties of the bricks was hardly detected, it became clear that reinforcement of the bricks' compressive strength and lowering of the bricks' capillary tube and movement were effective for long-term preservation.We have investigated the repair method of injecting repair materials into the unfilled joint parts of brick walls, a method which is generally adopted in brick buildings' preservation. In order to investigate the improvement in dynamic properties by this method, several bricks' materials and the mixing ratios of repairing materials for joint parts were provided. In addition, an unconfined compression test and a box shear test were performed using a brick masonry structure consisting of the brick and the jointing, in which various repairing materials were injected into the gaps in joint parts. Consequently, the difference in the fracture process between materials composing the masonry structure, and the great improvement of strength in the injected repairing materials, were confirmed. Less