대한민국의 도로의 증가로 인한 복잡화에 따라 터널의 수와 연장이 지속적으로 증가하고 있다. 본 연구는 시멘트콘크리트 포장의 성 능과 수명에 미치는 환경조건의 영향을 분석한다. 현재까지 시공된 고속도로의 많은 부분이 시멘트콘크리트 포장으로 되어 있으며, 이 에 대한 연구는 오랫동안 진행되어 왔다. 부등건조수축은 슬래브의 상하부 온습도 차이에 의해 발생하며, 일일 및 계절적 주기에 따라 발생한다. 일반적으로, 온습도 변화에 따라 컬링이나 와핑이 발생하는데, 컬링은 낮에는 높은 온도로 인한 하향 수축, 밤에는 낮은 온 도로 인한 상향 수축을 나타낸다. 그러나, 환경조건 변화에 따른 콘크리트 내부 습도 변화에 대한 이해는 아직 크게 연구가 진행되지 않아 포장 설계에 적절히 반영되지 못하고 있다. 이러한 연구는 터널 등 배수가 어려운 지역에서 콘크리트포장의 적절성을 판단하여 공용수명에 기여할 것으로 예상한다. 본 연구에서는 슬래브의 하부 조건이 콘크리트 내부 습도에 미치는 영향을 실험적으로 조사한다. 콘크리트 시편을 제작하여 특수한 환경조건에서의 습윤 차이를 모사하여 수분 이동 특성을 연구한다. 실험에서는 슬래브의 한쪽면을 고정하고 반대편이 부등건조수축으 로 인해 발생하는 변형률과 수직변위를 측정할 장비를 설치하여 시간에 따른 변화량을 확인한다.

In high-level radioactive waste disposal, a high temperature is generated from the canister containing the waste in the engineered barrier, while groundwater flows into the buffer system from the host rock. The temperature increase and groundwater inflow result in the water phase change and saturation variation. Saturation change is related to the thermal conductivity of buffer material; hence the phase change and saturation strongly interact with the temperature evolution. The complex coupled behavior affects the stability of the whole disposal system, and the security of the repository is critical to human-being life. However, it is difficult to predict the long-term coupled behavior in the disposal system due to the considerable field-test scale, and therefore a numerical simulation is a suitable method having repeatability and cost-effectiveness. DECOVALEX is an international cooperating project for developing numerical methods and models for thermo-hydro-mechanical-chemical (THMC) interaction. DECOVALEX has a four-year cycle with various topics. At the current phase, Task C aims to simulate the full-scale emplacement (FE) experiment performed at Mont Terri underground rock laboratory. Nine research groups are participating in the task, and among them, KAERI simulates the experiment using OGS-FLAC. The simulator combines OpenGeoSys for TH simulation and FLAC3D for M simulation. Through the benchmark simulation, we verified OGS-FLAC for the two-phase flow analysis in the disposal system and finally modeled the FE experiment with a three-dimensional grid. We performed a simple sensitivity analysis to investigate the effect of input parameters on the two-phase flow system and confirmed that the compressibility and permeability affected the flow behavior. We also compared the simulation results to the field data and obtained well-matched results from a series of simulation.

PURPOSES : It is well known that experts determined the current standard dimensions of freeway lane markings. However, rigorous engineering rationale could be insufficient regarding whether or not the standard dimensions account for how visible the markings are to the driver. In this study, we seek to optimize the dimensions of freeway lane markings to improve their visibility to drivers. METHODS: The study was conducted as follows. First, alternative lane marking dimensions were selected which could be installed in a test construction site. Second, a video recording was made while driving on the test construction site. Third, subjects were shown the recorded video and then instructed to indicate their preference from among the various lane markings. Lastly, t-tests were applied to assess the statistical significance of differences in the preferences expressed. RESULTS : According to the t-test results, there was no significant difference in the preferences expressed regarding the lane marking widths. However, with regard to the dimensions of freeway lane marking, which represents line marking lengths, gap lengths, and widths of marking, the subjects expressed a preference for specific dimensions such as 6 m:12 m,13 cm, 8 m:12 m,10 cm and 6 m:12 m,10 cm. CONCLUSIONS : In considering the dimensions of freeway lane markings and their relation to visibility by the driver, it was found that dimensions such as 6 m:12 m,13 cm, 8 m:12 m,10 cm and 6 m:12 m,10 cm.

In this study, the underground box culvert were selected in nine construction sites and the influencing factors of underground structures on concrete degradation were verified through the field and laboratory experiments.

The objective of this study was conducted to evaluate the effects of poultry litter amendments on pH and soluble reactive phosphorus (SRP) in poultry litter. Two laboratory studies were conducted for 42 d in Exp. 1 and for 10 d in Exp. 2, respectively. The poultry litter was treated with various amendments which included 4 g fly ash and 4 g AlCl3 (AlCl₃.6H₂O)/100 g litter in Exp. 1 and 4 g alum(Al₂(SO₄)₃.14H₂O), 8 g alum, 8.66 g liquid alum, and 17.3 g liquid alum/100 g litter in Exp. 2; untreated litter served as controls. There were no differences in pH between control and T1(4 g fly ash) and SRP contents between T1(4 g fly ash) and T2(4 g AlCl₃) in Exp. 1. A significant difference in pH and SRP contents in Exp. 2 was observed among all treatments(P< 0.05). In experiment 1, T1(4 g fly ash) and T2(4 g AlCl₃) at 42 d decreased SRP in litter by 47.1% and 62.6% of that from litter alone, repectively. In experiment 2, T1(4 g alum), T2(8.66 g liquid alum), T3(8 g alum), and T4(17.3 g liquid alum) treatments at 10 days reduced SRP contents by up to 36.2%, 62.9%, 87.0%, and 83.9%, respectively, when compared with the controls. Decrease in SRP contents was chiefly associated with reduction in litter pH. These results indicate that use of various litter amendments to limit P solubility has potential and should be pursued as a means of reducing soluble reative phosphorus during short term.

암석은 지표환경에 노출되면 오랜 세월동안 여러 요인에 의해 물리적 화학적 품화과정을 겪는다. 암석을 구성하는 광물 중 장석과 운모는 다른 광물들에 비해 가장 먼저 풍화되는 광물들이다. 자연계 풍화 화강암내에 존재하는 풍화 광물과 유사한 풍화 광물을 재현하기 위해 실내에서 신선한 광물과 산성용액과의 반응실험을 실시하였다. 흑운모의 경우, 낮은 pH조건에서 광물 용해 및 표면구조 파괴 현상이 초기에 시작되어 점차 진행되었고 사장석에서는 표면 침상 용해구조 발달 및 다량의 Al 성분의 침전물 형성이 두드러졌다. 강산조건에서는 모든 광물의 용해가 심화되었고 표면 용해구조가 뚜렷이 나타났다. 야외에서 관찰되는 광물표면의 용식각(etch pit) 및 표면 용해구조가 본 실험에서도 비슷하게 관찰되었고 광물 용해 및 풍화 조직이 광물 고유의 특성에 따라 발달됨을 알 수 있었다.