Thermal barrier systems have been widely investigated over the past decades, in order to enhance reliability and efficiency of gas turbines at higher temperatures. Yttria-stabilized zirconia (YSZ) is one of the most leading materials as the thermal barriers due to its low thermal conductivity, thermodynamic stability, and thermal compatibility with metal substrates. In this work, rare-earth oxides with pyrochlore phases for thermal barrier systems were investigated. Pyrochlore phases were successfully formed via solid-state reactions started from rare-earth oxide powders. For the heat-treated samples, thermo-physical properties were examined. These rare-oxide oxides showed thermal expansion of and thermal conductivity of 1.2~2.4 W/mK, which is comparable with the thermal properties of YSZ.

This Study reviewed the case of Gyeonggi-do province which recently induced Drone to pavement management system in order to research a plan to utilize recent technology Drone to pavement management system which is being operated depending on vehicles and manpower for 30 years. After filming video on local roads managed by Gyeonggi-do province by using Drone directly and created point cloud having three dimensional coordinate and color value through program analysis. Furthermore, this research showed that when we found similar color to point cloud at pavement crack part and applied color, crack part was detected.

We have identified the subway of structures as subway station users complained of vibrations from a structures when they walked through middle stairs of escalator. As a result of converting the vibration level to the conversion rate, it was measured at 3.846mm/s(82.7dB) on the B1st floor and 0.966mm/s(70.7dB) on the B2nd floor. These results are higher than the domestic standard of 65dB and lower than the international standard of under 5mm/s. It is felt well with the human body, but the structure is considered to be harmless. Therefore, it is deemded the structure is safe to usue. As the result of measuring the national frequency, the stairs on the B1st floor to be 3.01Hz and the stairs B2nd floor to be 5.36Hz. We consider that the users feel discomfort and anxiety on the B1st floor, where displacement and vibrations are higher.

There is also a reverse cavity in the back of the domestic subway and railways and roads, which cause a rift in tunnel structures due to stress concentration and strain. As a result, the balsaeng of the tunnel on the back of the tunnel was interpreted as a method to determine the method of a structural structure which greatly affects the stability of the tunnel structure.

There is also a reverse cavity in the back of the domestic subway and railways and roads, which cause a rift in tunnel structures due to stress concentration and strain. As a result, the balsaeng of the tunnel on the back of the tunnel was interpreted as a method to determine the method of a structural structure which greatly affects the stability of the tunnel structure.

In this study, the method of estimating impact coefficient is studied by dynamic load test using the results of inspection for railway bridge that have few errors that may occur in case of running of trains because trains move on the railway bridge.

In this study, ultrasonic detection device was applied to investigate connection part of concrete structure. Result of test, the internal void of connection part can be detected and it was possible to adopt the ultrasonic detection method to the maintenance of concrete structure.

It is to confirm the various causes for cracks in concrete lining and understand the reasons for major cracks by analyzing on-site constructional conditions. Also, it is to identify the bahavior of concrete lining for its main cause of cracks.

Existing tunnel and digging and construction of the center tunnel wall construction process was, including constructing additional a 2-Arch Tunnel is disadvantageous the workability and workday. In addition, the central wall (girder) due the complex waterproof, multiple, as leaks and has a structure plan requires proper Maintenance Methods.

교량의 장대화로 고품질과 양호한 시공성을 갖는 고유동성 매스콘크리트가 프리스트레스 콘크리트 거더에 광범위하게 사용되고 있으나, 수화열과 자기수축에 의한 비구조균열을 종종 발생하고 있다. 대상부재의 콘크리트응력에 대한 다양한 실험과 수치해석을 통하여 평가로부터 메스콘크리트의 수화열 증가에 따라 인장응력 및 균열지수를 예측하였다. 또한 분체계 혼화재료에 의한 자기수축 증가는 정착부 부근 매스콘크리트의 인장응력을 가중시킨다. 수화열과 자기수축 및 건조수축에 의한 인장응력은 PSC 거더의 대부분에서 약간의 응력증가를 나타내나, 정착부 근처의 인장응력은 콘크리트의 재령초기에 인장강도를 초과하게 되어 균열을 유발하게 됨을 알 수 있었다.

This study is that larger scale and longer span of construction in concrete structures urge increasing use of mass concrete, high-flowing concrete among them is more widely used for improvement of quality and concrete constructability, but it may cause occurrence of cracks due to autogeneous shrinkage as well as heat of hydration. In this regard, the present study provides comparative analysis on temperature characteristics subject to varied locations through experiments adopting a PSC girder in which high-flowing concrete is used; moreover, it analyzes heat of hydration through the FEM to perform the crack analysis of the PSC girder in such a way that the result thereof is compared with that of the experiment.