In this study, the correlation between the durometer and the proctor penetration resistance tester, which is considered to be efficient in determining the setting time in a simple portability for soil and concrete utilizing organic lime (H) and Goto lime (G), is used. The results of the study show a high correlation between the portable hardness meter, the durometer and the proctor penetration resistance test period. Therefore, it is expected that the durometer will be useful for the measurement of setting time and the time limit.

In this study, the correlation with a proctor penetration resistance tester is analyzed for the purpose of judging the setting time of concrete by the convenient portability of the durometer which is a rubber hardness meter.The result of this study showed a high correlation between the value of the tilt of the durometer and the measured value of the proctor penetration resistance tester.

In this study, the purpose of the study is to determine the depth of damage caused by early frost damage in concrete slab structures under the conditions of external temperature during winter. In other words, we intend to analyze the depth variation of the early frost damage as the thickness of the concrete slab member changes under the condition of the 3-component binder frequently used in practice. As a result, the thinner the component, the significantly reduced the overall temperature of the concrete. In addition, the thinner the component thickness, the higher the delay in increasing the brightness of the core collected from the concrete member, and the greater the effect on the depth of the early frost damage was on the thinner the component thickness.

As interest in sustainable concrete increases, research on replacing cement with alternative materials has been actively conducted. Therefore, in this study, flexural and compressive tests were carried out using sustainable specimens fabricated by replacing part of cement with blast furnace slag and activated Hwang-Toh as alternative materials and control specimen. Based on the test results, the specimen with blast furnace slag showed the best load-carrying capacity. Compared with the control specimen, the specimen with activated Hwang-Toh indicated about 94.8~102.1% load-carrying capacity. Thus, it appears that the sustainable concrete can be practically used in the construction field.

As interest in sustainable concrete increases, research on replacing cement with alternative materials has been actively conducted. Therefore, in this study, flexural and compressive tests were carried out using sustainable specimens fabricated by replacing part of cement with blast furnace slag and activated Hwang-Toh as alternative materials and control specimen. Based on the test results, the specimen with blast furnace slag showed the best load-carrying capacity. Compared with the control specimen, the specimen with activated Hwang-Toh indicated about 94.8~102.1% load-carrying capacity. Thus, it appears that the sustainable concrete can be practically used in the construction field.

Tissue equivalent proportional counter (TEPC) can measure the Linear Energy Transfer (LET) spectrum and calculate the equivalent dose for the complicated radiation field in space. In this paper, we developed and characterized a TEPC for radiation monitoring in International Space Station (ISS). The prototype TEPC which can simulate a 2 μm of the site diameter for micro-dosimetry has been tested with a standard alpha source (241Am, 5.5 MeV). Also, the calibration of the TEPC was performed by the 252Cf neutron standard source in Korea Research Institute of Standards and Science (KRISS). The determined calibration factor was kf = 3.59×10-7 mSv/R.