In case of high performance fiber reinforced cementitious composite(HPFRCC) specimens with steel fiber of 30mm they exhibited poorer flexural strength than the straight fibers at a higher than 1.5% compared to steel fiber of 13mm and 19.5mm. In this study, Therefore we evaluated the flexural strength and cracking behavior of HPFRCC with steel fiber type such as fiber length, volume fraction.

Aquatic plants serve the crucial function of helping to balance water reservoir ecosystem, as they filter and remove major minerals required for algal growth such as nitrogen, ammonia, and nitrates. Aquatic plants provide food, shade, and protection for the aquatic biome in and around the reservoir. Thus, it is important to accurately determine the existence and areal extent of the aquatic plants. In the present study drone-based facilities were used for this purpose. In the Muncheon water reservoir, Gyeongbuk, the Normalized Difference Vegetation Index (NDVI) and Surface Algal Bloom Index (SABI) were used to determine the existence status of the aquatic plants. The data so obtained exhibited reasonable accuracy; drone-based facilities can be used in future to identify the areal extent of aquatic plants.

The mechanical properties were evaluated to examine the optimum adding amount of AC and UT viscosity agent by mixing two viscosity agent according to the adding ratio. When the ratio of AC and UT viscosity agent was 5:5, It was most suited for high-fluidity concrete with low binders by increasing workability and effect of reducing viscosity.

The flowability and compressive strength were evaluated to examine the effect of biner mixing ratio on the high-fluidity concrete with low binders. When the binder mixing ratio (OPC, BFS, FA) was 7:2:1, It was most suited for high-fluidity concrete with low binders by increasing workability and compressive strength.

In recent years, in order to reduce self-weight of structural elements, the use of SCP(Steel Concrete Plate) is getting increased. Since SCP has complicated sectional shape and includes large amount of studs, the use of shrinkage reduction concrete is required. Therefore, in this study, to prevent the restrained shrinkage behavior by stud, the effects of using expansive agent (EA) and shrinkage reducing agent (SRA) was investigated.

In order to reduce self-weight of structural elements, the use of SCP(Steel Concrete Plate) is getting increased. Since SCP has complicated sectional shape and includes large amount of studs, the use of high-filling concrete is required. Therefore, in this study, It was evaluated the filling performance of filling concrete for SCP module according to our mix proportion. Resultingly, the concrete effectively filled the large-sized SCP module.

This study performed gas-gun propelled projectile impact tests with high strength steel fiber reinforced concrete. Also, from the impact tests, failure modes and protection performances of HIgh Performance Concrete which is reinforced by steel fibers were assessed. High strength steel fiber reinforced concrete showed excellent protection performances against impact loads.

The mechanical properties were evaluated to examine the optimum adding amount of AC and UT viscosity agent by mixing two viscosity agent according to the adding ratio. When the ratio of AC and UT viscosity agent was 5:5, It was most suited for high-fluidity concrete with low binders by increasing workability and effect of reducing viscosity.

The flowability and compressive strength were evaluated to examine the effect of biner mixing ratio on the high-fluidity concrete with low binders. When the binder mixing ratio (OPC, BFS, FA) was 7:2:1, It was most suited for high-fluidity concrete with low binders by increasing workability and compressive strength.

In recent years, in order to reduce self-weight of structural elements, the use of SCP(Steel Concrete Plate) is getting increased. Since SCP has complicated sectional shape and includes large amount of studs, the use of shrinkage reduction concrete is required. Therefore, in this study, to prevent the restrained shrinkage behavior by stud, the effects of using expansive agent (EA) and shrinkage reducing agent (SRA) was investigated.

In order to reduce self-weight of structural elements, the use of SCP(Steel Concrete Plate) is getting increased. Since SCP has complicated sectional shape and includes large amount of studs, the use of high-filling concrete is required. Therefore, in this study, It was evaluated the filling performance of filling concrete for SCP module according to our mix proportion. Resultingly, the concrete effectively filled the large-sized SCP module.

Drought is a reoccurring worldwide natural hazard that affects not only food production but also economics, health, and infrastructure. Drought monitoring is usually performed with precipitation-based indices without consideration of the actual state and amount of the land surface properties. A drought index based on the actual evapotranspiration can overcome these shortcomings. The severity of a drought can be quantified by making a spatial map. The procedure for estimating actual evapotranspiration is costly and complicated, and requires land surface information. The possibility of utilizing drone-driven remotely sensed data for actual evapotranspiration estimation was analyzed in this study. A drone collected data was used to calculate the normalized difference vegetation index (NDVI) and soil-adjusted vegetation index (SAVI). The spatial resolution was 10 m with a grid of 404 x 395. The collected data were applied and parameterized to an actual evapotranspiration estimation. The result shows that drone-based data is useful for estimating actual evapotranspiration and the corresponding drought indices.

선반 스크랩은 금속 가공 공정에서 선반 및 밀링 작업에 의해 발생된 철강제품의 부산물이므로, 섬유보강 시멘트 복합체 제작시 이 를 활용할 경우 경제성뿐만 아니라 환경 친화적인 효과를 가져온다. 따라서 이 연구의 목적은 강섬유 대체재료로서 선반 스크랩의 활용 방안을 제시하기 위하여 선반 스크랩 보강 시멘트 복합체(LSRCCs)의 작업성 및 강도 특성을 평가하는 것이다. 이를 위하여 금속 가공공장에서 3종류 의 선반 스크랩을 채취한 후 폭 2 mm, 길이 40 mm로 가공하여 LSRCCs를 제작하였다. 그 결과, LSRCCs의 작업성은 플레인 모르타르보다 약 간 저하되었고, 휨강도는 크게 개선되었으며, 선반 스크랩의 종류가 LSRCCs의 특성에 다소 영향을 미치는 것으로 나타났다.

In this study, We evaluated the impact resistance of structural member using high performance fiber reinforced cementitous composite according to compressive strength. As the compressive strength of structural member using HPFRCC increased, the deflection of the structural member decreased. The highest resistance of deflection occurred at 180 MPa HPFRCC.

Since the scale and disaster characteristics of volcanic eruptions are determined by their geological features, it is important not only to grasp the current states of the volcanoes in neighboring countries around the Korean Peninsula, but also to analyze the tectonic settings, tectonic regions, geological features, volcanic types, and past eruptional histories of these volcanoes. We created a database of 285 volcanoes around the Korean Peninsula, and then identified a high-risk groups of 29 volcanoes that are highly likely to affect the region, based on conditions such as volcanic activity, the type of rocks at risk of eruption, the distance from Seoul, and high VEI (volcanic explosivity index). In addition, we identified the 10 volcanoes that should be given the highest priority. We selected them through an analysis of data available in literature, such as volcanic ash dispersion results from previous Japanese eruptions, the definition of a large-scale volcano used by Japan’s Cabinet Office, and examination of cumulative magma layer volumes from Japan’s quaternary volcanoes.

The objective of this study was to investigate the 16 priority polycyclic aromatic hydrocarbon (PAHs) concentrations and emission sources from the soils of three regions (north, mid-south, and east) in Jeollanamdo. Overall PAH concentrations in the east region were higher than in north and mid-south regions and 9.1 times higher for polluted areas. The results of the emission source study indicated that average Ant/(Ant+Phe) and InP/(InP+BghiP) ratios were 0.15-0.22 and 0.36-0.46, respectively, which indicated dominant pyrogenic sources in the three regions. For the InP/(InP+BghiP) ratio, various emission sources were shown in the east region where petrochemical facilities and oil storage tanks have been operated.

The purpose of this experimental research is to investigate the effect of types of lathe scrap on the characteristics of lathe scrap reinforced cementitious composites (LSRCCs). For this purpose, three types of lathe scraps were collected from processing plants of metal, and then LSRCCs containing these were made for 2mm width and 40mm length. As a result, it was observed from the test results that the compressive and flexural strength of LSRCCs were larger than these of plain mortar and effect of types of lathe scrap on the characteristics of LSRCCs were slightly large.

This research intends to develop a photocatalytic concrete enabling to decompose the nitrogen oxides (NOx) using a titanium oxide photocatalyst for reducing the cost. In details, this research develops the mix composition of the photocatalytic concrete exhibiting photolytic characteristics and establish the technology enabling to reduce the emission of air pollutant caused by nitrogen oxides.

This paper presents an experimental study on the improvement of ductile and flexural strength for high performance fiber reinforced cementitous composites (HPFRCC). The test was evaluated by compressive and flexural behavior of HPFRCC(compressive strength : 180 MPa) according to aspect ratio and volume contents of steel fiber. The flexural strength was increased by aspect ratio near 100 or increasing volume contents of steel fiber while there is no clearly result on the compressive strength.

공공시설물의 대형화 및 도심지로의 인구 밀집화에 따라 충돌 또는 폭발과 같은 하중조건 하에서의 구조물 방호성능의 중요성이 대두되고 있다. 그러나 구조물의 방호설계 및 시공에 있어서 필수적이라 할 수 있는 구조 재료 또는 자재에 대한 방호성능 평가기준은 현재 정 립되어 있지 않은 실정이다. 따라서 본 연구에서는 구조용 자재의 내충격 성능평가 기준 개발 연구의 일환으로 가스건을 사용한 발사체 충격 파 괴시험을 콘크리트 시험체에서 수행함과 동시에, 다양한 접촉식 계측 센서의 적용 가능성을 확인하고자 하였다. 또한, 충격 파괴시험을 통해 일반 콘크리트 및 강섬유가 보강된 초고성능콘크리트의 파괴모드 및 방호성능에 대한 평가를 수행하였다. 실험 수행 결과, 접촉식 계측센서 중 LVDT 변위계의 적용 가능성을 확인하였으며, UHPC의 경우 혼입된 보강섬유의 효과로 인해 일반 콘크리트에 비해 우수한 방호성능을 보여주 었다.