PURPOSES : This study is conducted to evaluate the development of materials for extinguishing ESS(Energy Storage System) fires in electric vehicles using industrial byproducts. METHODS : Grout containing an appropriate amount of fly ash, silica fume, blast furnace slag powder, and ferronikel slag, which are industrial byproducts, was prepared. The fluidity, stress, and mechanical properties were evaluated in accordance with standard test methods. RESULTS : The fluidity of the materials used for the evolution of ESS fires differed depending on the material of the industrial byproducts. In the case of blast furnace slag, its fluidity is low owing to viscosity even when it content is high, and the use of ferronikelsrag is shown to be suitable for the evolution of ESS fires in fluidity and curing tests. CONCLUSIONS : Fire-extinguishing materials using industrial byproducts require a long curing time but exhibit the fluidity required for ESS fire extinguishment. In particular, the curing and fluidity of Peronikel slag and fly ash are suitable for ESS fire extinguishing.

PURPOSES : Safety Evaluation of Wind Loads of Renewable Energy and Photovoltaic Power Structures. METHODS : Structural safety evaluation was conducted on the wind load of 3kW Photovoltaic Power Structures using ABAQUS. Wind speed was reviewed for 36m/s and 60m/s. Effective Mass and Mass Contribution of Photovoltaic Power Structures was utilized up to 90%. 7 steps were set and applied to structural analysis. RESULTS : As a result of the structural analysis, it was confirmed that the long-term blowing load was affected rather than the size of the wind load. Weak areas were identified at the point of the horizontal beam rather than the modules of the Photovoltaic Power Structures. In particular, it was confirmed that stress exceeding the allowable stress was generated at the junction. In order to secure the safety of Photovoltaic Power Structures, it is judged that reinforcement of the branch is necessary. CONCLUSIONS : The safety of Photovoltaic Power Structures structures for wind load is influenced by persistence rather than the size of the wind load. Therefore, in order to prevent this, it is judged that reinforcement of the branch is necessary.

PURPOSES : In this study, high-viscosity grout for increasing ground stiffness is developed using industrial byproducts. METHODS : Based on literature review, the viscosity and viscosity expression time of domestic and foreign anti-washout admixture underwater were evaluated. In addition, grout was prepared by mixing 5% to 40% of fly ash (FA) in a standard mixture. Flow, setting time, and compressive strength tests were conducted to evaluate the quality of the grout. RESULTS : Experimental results show that the viscosity required is 35,000 to 40,000 cps, whereas the viscosity expression time required exceeds 300 min. As the amount of FA used for grouting increases, the physical and mechanical performances deteriorate. The strength of a test specimen manufactured underwater is lower than that of a test specimen manufactured under air, and the decrease on day 28 is lower than that on day 3. The FA applied to the grout should be less than 20%. CONCLUSIONS : Although industrial byproducts, which exhibit high viscosity, offer excellent mechanical performance and are thus suitable as a solidifying agent for strengthening grout, their application in the field must be evaluated.

PURPOSES : The objective of this study is to evaluate the performance of combined organic and inorganic hybrid mortar used as repair materials (UM mortar) for concrete road facilities by comparison with cement repair materials (RM mortar). METHODS: In order to produce UM mortar, four different levels of inorganic materials were adopted and the ratio of main resin to hardener was fixed at 1:2. For comparison, RM mortar made with cement repair materials was also produced. Fluidity, strength characteristics, length change, and freezing-thawing resistance of the mortars were measured at the predetermined periods. In addition, the microstructures of the mortars was performed on the 28-day mortar samples to examine the properties of the interfacial transition zone (ITZ). RESULTS : It was observed that the mechanical properties, except for compressive strength, and freezing-thawing resistance of UM mortars were much better than those of RM mortar. Furthermore, showing a densified ITZ properties on the UM mortars from the microstructural observation, the usage of UM mortars exhibited a beneficial effect on the enhancement of mortar properties. CONCLUSIONS: It is concluded that the application of combined organic and inorganic hybrid mortars is a possible option for the repair of deteriorated concrete road facilities.

PURPOSES : Durability of concrete is traditionally based on evaluating the effect of a single deterioration mechanism such as freezing & thawing action, chloride attack, carbonation and chemical attack. In reality, however, concrete structures are subjected to varying environmental exposure conditions which often results in multi-deterioration mechanism occurring. This study presents the experimental results on the durability of concrete incorporating air-cooled slag(AS) and/or water-cooled slag(WS) exposed to multi-deterioration environments of chloride attack and freezing & thawing action. METHODS: In order to evaluate durable performance of concretes exposed to single- and multi-deterioration, relative dynamic modulus of elasticity, mass ratio and compressive strength measurements were performed. RESULTS: It was observed that multi-deterioration severely affected durability of concrete compared with single deterioration irrespective of concrete types. Additionally, the replacement of cement by AS and WS showed a beneficial effect on enhancement of concrete durability. CONCLUSIONS : It is concluded that resistance to single- and/or multi-deterioration of concrete is highly dependent on the types of binder used in the concrete. Showing the a good resistance to multi-deterioration with concrete incorporating AS, it is also concluded that the AS possibly is an option for concrete materials, especially under severe environments.

최근, 시멘트 사용량을 줄이고, 경제성을 확보하기 위하여 혼화재료를 적용한 콘크리트 포장에 대하여 많은 연구가 이루어지고 있다. 국내외적으로 콘크리트 포장용 결합재로써 활용되어지고 있는 혼화재료로써 고로슬래그, 플라이애시 등이 있으며, 이 중 고로슬래그는 냉각방법에 따라 급수로 냉각처리된 급냉슬래그와 공기 중에 냉각처리된 서냉슬래그로 분류될 수 있다. 서냉슬래그는 화학조성이 급냉슬래그와 유사하고 염기도가 높아 콘크리트용 혼화재료로 사용될 경우, 콘크리트 중 수산화칼슘과의 잠재수경성 발현에 유리하여 콘크리트 포장용 결합재로써 활용이 가능할 것으로 보고되고 있으며, 서냉슬래그의 물리화학적 특성을 기반으로 하여 서냉슬래그를 콘크리트 포장재료로써 활용하기 위한 몇몇의 연구가 진행되어 오고 있다. 본 연구에서는 서냉슬래그를 콘크리트 포장재료로 사용하여 공시체를 제조하였으며, 콘크리트의 공학적 특성을 실험적으로 평가함으로써, 서냉슬래그의 콘크리트 포장재료로써 적용가능성을 실험적으로 검토하였다.

PURPOSES : This paper aims to develop a road pavement de-icing system using carbon sheet to replace the older snow de-icing method. Carbon sheet is a light and high-strength metal. Hence, various bodies of research for its applications in many industries have progressed. METHODS : The experiment was conducted in a laboratory. The carbon sheet supplied voltage through a power supply system, and produced heat transfers to the concrete surface. Various factors, such as pavement material, carbon sheet width, penetration depth, and freezingthawing resistance, were considered in the conducted experiments to confirm the heating transfer efficiency of the carbon sheet. RESULTS : The carbon sheet used was a conductor. Therefore, it produced heat if voltage was supplied. The exposed carbon sheet on the atmosphere did not affect the carbon sheet width when it provided constant voltage. However, the sheet showed different heating behaviors by width change when the carbon sheet penetrated into the concrete. Moreover, the freezing-thawing resistance was decreased by the carbon sheet with increasing width. CONCLUSIONS : The experiments confirmed the possibility of developing a road snow melting system using a carbon sheet. The antiicing system using the carbon sheet to replace the traditional anti-icing system has disadvantages of environmental pollution risk and electric leakage. The pavement also improved its toughness resistance. The utilization value will be very high in the future if carbon sheet heat loss can be minimized and durability is improved.

This study is to analyze the causes of damage on additional facilities in road. In this study, lab test was performed using field core sample. The result of The compressive strength of concrete is met with the design regulations. However, the chloride content of in concrete increased up to 2cm. The microstructure and reactant analysis identified an expanding substance on the surface. However, as the time increases, the depth is expected to be deep.

This thesis will provide the baseline data of a suitable road repairing solution by analyzing the freeze-and-thaw resistance of inorganic-organic hybrid mortar. The resilience of polymer mortar and high-elastic mortar to freeze thaw resistance showed that the high-elastic mortar showed excellent resistanc

This research provides the baseline data for choosing the inorganic/organic hybrid material as the repairing solution by analyzing its efficiency in securing high vibration resistance and very low permeability. As a result of analysis of the mechanical properties of hybrid composite mortar, the strength increased with age. Therefore, it is considered that an inorganic binder having a certain amount or more is required for high strength development.

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.

원형 구조물의 보수/보강 및 FRP를 구조부재로 활용한 신설 구조물 시공을 위해서는 일정한 곡률반경을 갖는 곡면 FRP 부재가 요구된다. 그러나 현재까지 FRP 곡면부재는 수작업 (hand-lay-up) 또는 필라멘트 와인딩 (filament winding) 작업에 의해서만 생산이 가능하였으며, 대량 연속생산에는 한계가 있다. 또한 일반적으로 인발성형법 (pultrusion method)으로 생산된 FRP 부재가 상대적으로 물리적 특성이 우수한 것으로 알려져 있다. 따라서 FRP 부재를 일정곡률을 유지하며 인발로 뽑아낼 수 있는 신개념의 곡면 FRP 부재 인발성형법 제안 및 성형장비를 개발, 곡면 FRP 제품을 생산하였으며, 본 연구에서는 곡면 FRP 부재를 이용한 구조물 보수/보강시 야기될 수 있는 FRP와 콘크리트 부착면의 동결융해 영향을 분석하였다.

본 연구에서는 alkali-free 및 aluminate 급결제를 사용한 OPC 및 GGBFS 숏크리트 모르타르의 응결특성, 강도특성, 전기저항성 및 염소이온 침투저항성을 실험적으로 고찰하였다. 실험결과에 따르면, alkali-free 급결제를 첨가한 GGBFS 모르타르는 응결시간 및 압축강도가 GGBFS 대체율에 관계없이 OPC 모르타르와 유사하게 나타났으나, aluminate 급결제를 첨가한 모르타르의 경우, GGBFS 대체율이 증가할수록 응결시간 및 압축강도가 크게 나타나는 경향을 보였다. 한편, 숏크리트 모르타르의 전기저항성 및 염소이온 침투저항성은 GGBFS를 50% 이상 대체한 모르타르가 우수한 경향을 나타내므로써, 적절한 대체율의 GGBFS를 사용한 모르타르가 숏크리트용 재료로써 우수한 성능을 나타낼 것으로 판단된다.

This paper presents the experimental results for durability of an NaOH designed with blast furnace slag through the test method of chloride ion resistance and freezing-thawing resistance, Carbonation. In order to compare with NaOH, normal concrete was also tested. Test results showed that NaOH exhibited lower durability performance than ordinary mortar.

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.

Utilization of the fiber reinforced polymer(FRP) material has been enlarged as a substitution material to the general construction materials having certain long-term problems such as corrosion, etc. However, it could be difficult to apply the FRP material, which has a linear shape generally, to an arch or circle-shaped structure. Therefore, an attempt has been made in this study to develop a device to form a designed cross section of FRP material by pulling out with a curvature. A member of the curved FRP product was successfully produced and then strengthened intake tower by curved FRP members.

Concrete is generally accepted to have good fire resistance. It mainly relies on the assumption that concrete has low heat-transfer characteristic and spalling does not occur during the course of a fire. However, the significant numbers of fire accidents have shown in recent years that incidence of spalling has caused sever damages to many structures. This research has investigated a series of catastrophic tunnel fires and tested on the behaviour properties of concrete in association with loading in fire. This paper present that the theoretical consideration and experimental results are used the information of concrete spalling.