Environmental pollution has led to global warming, which threatens human life. In response, hydrogen is gaining attention as a next-generation energy source that does not emit carbon. Due to its explosive nature, special care must be taken in the safe storage and transportation of hydrogen. Among various storage methods, liquefied storage, which can reduce its volume to 1/800, is considered efficient. However, since its boiling point reaches -253°C, the design of an insulation system is essential. For the design of insulation systems applied to large containers, a membrane-type design is required, which necessitates the use of cryogenic adhesives. To evaluate whether the cryogenic adhesive is properly implemented, assessments such as tensile and shear tests are necessary. This study presents a methodology for shear evaluation. Conventional methods for shear evaluation of adhesives result in slippage, preventing proper assessment. Therefore, a method involving drilling holes in the gripper and pulling from the holes must be applied. Optimal design concerning the size and location of the holes is required, and this study derives optimal values based on finite element analysis. By conducting experiments based on the results of this study, it is expected that the risk of gripper damage will be minimized, allowing for accurate evaluation of the adhesive’s performance.

URPOSES: The objective of this study was to develop an impact resonance (IR) test procedure for thin disk-shaped specimens in order to determine the ⎢E*⎢ and phase angle values of various asphalt mixtures. METHODS: An IR test procedure was developed for evaluating thin disk-shaped specimens, in order to determine the dynamic modulus (⎢E*⎢) of various asphalt mixtures. The IR test method that was developed to determine the elastic modulus values of Portland cement concrete was evaluated, which method uses axisymmetric flexural vibration proposed by Leming et al. (1996). The IR tests were performed on three different mixtures of New York with varying nominal maximum aggregate sizes (NY9.5, NY19, and NY25) at six different temperatures (10 - 60℃). The ⎢E*⎢ values obtained from the IR tests were compared with those determined by the commonly used AASHTO T342-11 test. RESULTS AND CONCLUSIONS : The IR test method was employed to determine the ⎢E*⎢ values of thin-disk-shaped specimens of various asphalt mixtures. It was found that the IR test method when used with thin disk-like specimens is a simple, practical, and cheap tool for determining the ⎢E*⎢ values of field cores. Further, it was found the ⎢E*⎢ values obtained from the IR tests using thin disk-like specimens were almost similar to those obtained using the AASHTO T342-11 test.

본 연구는 길이 1m의 SD400 D13, D10 철근 시편의 중앙 20cm를에 염화칼슘(CaCl2–10%)과 10V의 전압을 인가하여 부식을 촉진시킨 수, 부식으로 인해 줄어든 단면적과 철근의 인장 거동과의 관계를 파악하기 위한 것이다. 9주 동안의 실험을 통해 평균 15.57%의 단면 손실을 이루었으며, 이때 부식이 진행된 시편에서 항복응력의 저하, 탄성계수 감소 등의 현상이 나타난 것을 확인할 수 있다.