For insulation to concrete, lightweight aggregate and the hollow microspheres were mixing to improve the insulation performance. Hollow microspheres according to the replacement method and the replacement ratio was to compare the degree of performance improvement.

This study was carried out to evaluate effects of curing method and age on compressive behavior of steel fiber reinforced Alkali-Activated Slag(AAS) concrete. AAS and Steel Fiber Reinforced Concrete (SFRC) material with specific compressive strength of 30MPa was reinforced with 0% to 1% steel fibers at the volume fraction. Two types of curing methods were used: water curing and exposed curing. Curing time is 3, 7, 28 day. Experimental results indicated that compressive strength, elastic modulus, compression index.

The priority order about a rational repair and reinforcement is generally decided by subjective decision of engineer. An appearance investigation carried out to decide about a rational repair and reinforcement through systematic and objective analysis in tunnel. we could prevent expecting leakage through several improvements in the aspects of design, materials and site implementation.

In order to efficiently use a limited budget for bridge maintenance, a systematic decision-making method is proposed considering the performance of individual bridges and their direct and indirect values. The method can be expected to lead a quantitative decision-making in maintenance phase of bridges.

The amount of newly-built bridges has been gradually reduced so that the importance of maintenance for existing bridges which has a long services period is issued. Therefore, the maintenance budget for existing bridges is going to be consistently increased. It is needed that a reasonable decision-making methodology for existing bridge maintenance is required to effectively use the limited maintenance budget. In this study, a method of the structural vulnerability evaluation is newly suggested as the one of the evaluation stage for developing a reasonable decision-making methodology.

The local displacement in the downstream of the embankment dam has been observed since the 2nd precise inspection was investigated. It appears that this displacement is caused by the differential settlement on the different properties of the zone during the construction. Therefore, using the advanced inspection method of the 3D scanning determines whether to proceed with the displacement. In this study, reviewing a field application and analyzing results of the 3D scanning method are drowned a conclusion for improvement in the inspection and maintenance method on the Rock-fill type embankment dam.

This study proves that the prestress loss occurs at the continuous joint by the local bending of tendon due to the construction deviation and the curvature of radius. Also, a method that can reduce the prestress loss is proposed, and proved by the experiment.

In case of measuring strength of concrete using ultrasonic pulse testing, setting reasonable range of limitations to get reliable strength data results is highly recommended. To resolve this issue, ultrasonic testings were performed on several concrete specimens ,randomly selected and contain strength ranged from 20 to 200MPa, to measure values of ultra sonic velocity and actual strength. Then advanced data analyses were performed based on the results from the experimental works.

In this Study cable tension of existing cable-stayed bridge is measured by non-contact laser vibrometer, and applicability of a non-contact vibration measurement method is experimentally evaluated. According to the analysis results, the non-contact vibration measurement method reveals an error of less than 5%, and could be efficiently applied to a rapid measurement for nonstationary response analysis of bridge structures.

In this study, a new damage detection method using an inclinometer which can directly measure rotational displacement is developed and its effectiveness investigated. In order to verify the attractive features of the proposed method such as an increase in sensitivity and the data loss minimization, numerical analyses were performed by the uniform load surface curvature (ULSC) method, which is the damage detection method based on the modal flexibility matrix. For numerical analysis, 2 m simply supported beam, which has 20 elements and 21 nodes is considered. From the results of the eigenvalue analysis, the damage locations were perfectly detected in each damage case. It shows that the damage detection using rotational displacement is theoretically possible. From the result of numerical simulations, the damage locations were detected exactly. When compared with the detection method based on vertical displacements obtained from accelerometers, it is shown that using the rotational displacement is much more sensitive than using the vertical displacement. Overall, when compared with the accelerometer data, the damage detection performed by an inclinometer was more sensitive.

As the building maintenance and safety management have recently been brought to attention, the utilization of non-destructive testing methods for internal inspection of concretes is increasing. Non-destructive testing methods, unlike typical destructive testing methods that deconstruct or cut the building in case of issues such as pores, heterogeneous material, cracks or any such equivalent issues inside/outside the building, refer to the testing methods for pores, heterogeneous material, or defectiveness occurring in the specimen without changes or destruction of internal structure using ultrasound, radiation, electromagnetism, fluid, heat, or light. In this study, among such non-destructive testing methods, the impact echo method was used for an experiment to estimate the steel rebar location and thickness in the concrete mock member.

화장품에 배합되는 원료 중에 피부 모공을 막아 여드름의 초기단계인 면포를 유발함으로써 염증성 여드름으로 악화시키는 사례가 보고되고 있다. 본 연구는 ‘여드름 피부에 사용이 적합한’ 면포 비유발성 화장품의객관적인 평가 기준을 마련하고자 하였다. 외국 임상기관에서 실시하고 있는 non-comedogenic test를 조사하고 등 상부 반복 폐쇄 첩포를 통해 면포 유발 평가방법을 확립하고자 연구를 수행하였다. 또한 안면부 사용성시험을 동일 피험자에게 추가로 진행하였다. 등 상부 반복 폐쇄 첩포를 통해 면포를 채취하여 분석한 결과 시험시료로 사용한 보습제와 자외선 차단제가 면포를 유발하지 않음을 확인할 수 있었고, 동일한 시험제품을 안면부에 사용하여 얻은 면포 유발 결과와 Global acne grading system (GAGS)의 여드름 육안평가 결과는 상관관계가 없었다. 또한 사진 판독을 통해 분석하는 면포와 모낭의 구별을 용이하게 하기 위해 면포 채취 표본에 Oilred O staining을 실시하였다. 염색을 한 경우의 표본이 염색을 하지 않은 표본과 비교하여 결과 간 높은 일치도를 확인하였다. 본 연구에서는 Oil red O staining을 통해 객관성과 신뢰성을 증진시킨 새로운 버전의 화장품면포 비유발성 평가법을 확립하였다.

In this study, the risk factors which derive from the ground condition of typical construction sites are put forward. In order to prioritize the risk elements, the analytical method of AHP was used. The result of using a weighting factor for each risk analysis showed that if the constituency index is less than 0.1, then reliable results and priorities for each of the risk elements can be calculated using the AHP method. From now on, if the range of measured value can be established, the risk or safety value of concrete structures for power lines can be applicable.

The road icing forecast and snow detection system using state evaluation algorithm of multi sensor optimizes snow melting system to control spread time and amount of chemical spread application This system operates integrated of contact/non-contact sensor and infrared camera. The state evaluation algorithm of the system evaluates road freezing danger condition and snowfall condition (snowfall intensity also) using acquired data such as temperature/humidity, moisture detection and result of image signal processing from field video footage. In the field experiment, it proved excellent and reliable evaluated result of snowfall state detection rate of 89% and wet state detection rate of 94%.

In this study, the applicability of impact-echo method for assessment of residual strength of fire-damaged concrete is investigated. A series of standard fire test is performed to obtain fire-damaged concrete specimens. Impact-echo tests are executed on the specimens and the responses are analyzed. Compressive strengths of the fire-damaged concrete are evaluated and correlated with the ultrasonic wave velocities determined from the impact-echo responses. The effectiveness of impact-echo based ultrasonic wave velocity measurement for assessment of residual strength of fire-damaged concrete is discussed.

미국 오바마 대통령은 2013 국정연설에서“3차원(3D)프린팅(printing) 기술육성으로 새로운 제조업 혁명을 이룰 것”이라고 선언했다. G2인 중국 또한 3차원(D) 프린팅 기술 투자로 제조 산업을 일으키겠다고 의지를 표명했다. 대한민국은 3D프린팅에 대한 연구가 미흡한 실정으로 국가전략 및 미래 산업동력으로서 3D프린팅 모델링 연구를 제안하는데 목적이 있다. 연구방법은 국내외 3D프린팅 사례를 분석시트에 적용하여 종합적인 연구를 시도한다. 연구결과 3D프린팅은 소재별로 세부제작 방식이 광 조형공정, 분사시스템, 선택적 레이저 소결, 직접금속레이저소결, 3차원인쇄, 융합증착모델링으로 분별된다. 종합적 특징으로는 일반적인 제조공정에 비하여 제작 속도, 제품의 정확한 형태, 표면마감정도, 재료의 다양성과 색상이 우수하다. 조형적 특징은 오브젝트 내부에 오브젝트, 섬유 직접조형효과 인쇄와 개별 색상구현, 움직이는 부품의 동시구축, 복재3D 스캐닝 및 자유로운 스케치 조형구축등이며 기능적이고 혁신적인 디자인이 가능하다. 3D프린팅은 개인맞춤형, 1인 제조, 혁신적 디자인, 새로운 제조영역으로서의 가능성과 대한민국의 미래 성장 동력으로서 가치를 지니고 있다.

수돗물의 생산 및 공급과정에 소요되는 에너지에 대한 체계적인 분석 및 평가는 최근의 전력부족 사태와 온실가스 감축의 필요성에 따라 관심이 증가되고 있다. 본 연구에서는 기존의 연구에서 제시한 결과에 대한 검토를 통하여 실용적으로 적용 가능한 에너지 분석기법 및 평가기법을 제시하였다. 본 연구에서는 EPANET2의 수리해석 결과를 이용하여 에너지를 평가할 수 있는 모형을 MATLAB 플랫폼 기반 하에서 개발하였다. 제안된 기법은 상수관망의 입지, 관로의 상태, 누수정도 등에 따라 시설물이 내재적으로 가지는 에너지 관리효율과 운영효율을 분리하여 평가할 수 있는 성능평가 지표를 제시하였다. 개발모형은 시험관망과 실제관망에 대하여 각각의 상수관망 구성요소에 대한 에너지 분석 및 평가결과를 제시함으로써 적용성 평가를 실시하였다. 본 연구의 결과는 상수관망 에너지 관리의 최적화를 도모함으로써 피크시간대의 전력수요 관리 및 에너지 절감형 상수도 시스템 계획 및 운영에 활용될 수 있을 것으로 기대된다.

In this study, corrosion potential (Ecorr), corrosion rate, and polarization resistance were measured aimed at inorganic inhibitors (passive film type) and organic inhibitors (absorption type). The experiment was conducted using potentiostat for the variable molar ratio and chloride ion concentration of the components of inhibitors in an aqueous solution of saturated calcium hydroxide targeting corrosion. As a result, it was possible to ensure an anticorrosive performance of at least a 1.2 molar ratio of inorganic inhibitors. Also, the organic inhibitors ensured the prevention of the anticorrosive performance of at least about a 0.3 molar ratio. It also showed the tendency that between polarization resistance and corrosion rate, Ecorr and corrosion rate is inversely proportional to the linear. Conversely, the tendency between polarization resistance and Ecorr is proportional to the linear. Also, a distinct difference in organic and inorganic inhibitors’ relationship to Ecorr, corrosion rate, and polarization resistance was not shown.

Prestressed concrete (PSC) members are readly available in civil engineering applications due to the convenience of construction and easy of quality control in the manufacturing process of the member. Especially, half-depth precast concrete composite slab, which is one of the PSC flexural members is developed recently using the long-line method. The half-depth precast concrete composite slabs are composed of the precast concrete and the in-situ concrete placed at the site. In this paper, we present the results of experimental investigations pertaining to the pretensioning efficiency and the flexural behavior of half-depth precast concrete composite slab which is made of precast PSC manufactured by the long-line method. In the long-line method, the pretensioned precast member is manufactured simultaneously, by tensioning tendons at once. In addition, we suggest the equation that can estimate the flexural strength of half-depth precast concrete composite slab reasonably by considering the effects of rebar embedded in the precast PSC flexural member.

본 연구에서는 기후변화에 따른 수자원 영향평가를 위한 지역기후모형과 단계적 스케일링기법을 연계한 혼합상세화기법을 개발하고 그에 따른 적용성을 평가하고자 하였다. 단계적 스케일링기법은 강수량 구간을 총 3구간(극치호우사상, 무강수일수, 기타)으로 나누어 각 구간에 따라 각기 다른 방법을 적용하여 보정하는 기법으로, 극치호우사상은 회귀식을 이용한 보정기법, 무강수일수는 분위사상법, 나머지 부분은 평균 및 분산보정 기법을 적용하였다. 이 기법의 비교‧평가를 위해 최근 혼합 상세화기법으로 가장 많이 적용되고 있는 선형보정기법, 분위사상법, 일기상발생기법을 활용하여 기상청 관할 기상관측소 61개 지점을 대상으로 적용성 평가를 수행하였다. 평가 결과, RCM에서 생산된 원자료 및 3가지 기존 기법(선형보정기법, 분위사상법, 일기상발생기법)으로 보정된 기후시나리오에 비해 본 연구에서 제안한 단계적 스케일링기법이 실제 기후특성을 잘 모의하는 것으로 나타나 적용성이 우수한 것으로 판단된다. 이러한 연구결과를 통해 단계적 스케일링기법은 RCM 사용이 증대될 기후변화 연구에 있어 그 활용성이 높을 것으로 기대된다.