이 연구는 코르크보드를 보강하여 건축부재 및 놀이기구의 안전부재 등으로 폭넓게 활용할 것을 목적으로 코르크보드의 중층에 금속, 유리섬유, 탄소섬유를 삽입하여 보강한 3종의 코르크복합보드를 제조하였고, 코르크복합보드의 수분흡수에 따른 치수안정성 및 접착층 박리성능을 조사하였다. 코르크복합보드의 흡수율은 0.37% - 0.45%의 범위에 있었고, 코르크보드에 비해 0.61배 - 0.74배의 낮은 값을 나타내었다. 코르크복합보드의 두께팽창률은 0.92% - 1.58%의 범위에 있었고, 코르크보드 보다 1.4 - 2.4배의 높은 값을 나타내었다. 그러나 이 값들은 일반 목질보드보다 현저히 낮았고, KS규격의 12%이하를 하회하는 것이 확인되었다. 코르크복합보드의 준내수 및 내수침지박리시험후의 접착층박리율은 0%로 전혀 접착층의 박리가 일어나지 않아 우수한 내수성을 나타내었고, 흡수율과 흡수두께팽창률은 상온침지에 비해 다소 증가하였으나, 목질보드에 관한 KS규격을 하회하는 우수한 치수안정성을 나타내는 것이 확인되었다.

유리섬유강화 모르타르 관을 구성하는 보강섬유는 직교이방성 부재로 간주되며 재료의 성질은 서로 직각을 이루는 두 개의 축을 기준으로 정의된다. 유리섬유 모르타르 관의 구조적 거동 해석을 수행하기 위해서 길이방향과 원주방향의 재료의 역학적 성질, 즉 탄성계수, 전단탄성계수, 포아송비 등이 필요하며 각각의 성질들은 실험을 통해 결정하였다. 이 실험으로부터 구한 각각의 역학적 성질을 적용하여 간소화된 유한요소해석방법을 제안하기 위해 적층판 이론으로부터 유리섬유강화 모르타르 관의 탄성계수를 계산하고, 계산된 탄성계수를 적용하여 유한요소 해석을 수행하였다. 또한, 유한요소해석과 편평시험을 통해 구한 하중-변위 관계를 비교하였으며 ASTM D2412에서 제시하고 하고 있는 관의 강성 값을 유한요소해석과 실험을 통해 예측하여 비교하였다.

GRP관은 연성관으로 분류되며, 지중에서 지반과 함께 외부하중에 저항하는 상호거동을 한다. 또한 국내 설계기준에서는 GRP관의 설계에 대한 명확한 규정을 제시하지 못하고 있으나, AWWA M 45 및 ASTM D 2412에서는 지중매설 GRP관의 관변형에 대한 주요설계변수를 관강성, 지반반력계수, 기초각 등으로 규정하고 있다. 이 연구에서는 지중매설된 연성관의 구조적 거동을 파악하기 위하여 기존 연구에서 수행한 연구결과와 AWWA M 45에서 제시하고 있는 설계식을 이용하여, 관강성, 지 반반력계수, 기초각계수를 변수로 지반-관 상호작용 특성을 검토하였다. 검토결과 지중매설 GRP관의 구조적 거동에 가장 큰 영향을 미치는 설계변수는 지반반력계수이고, 기초각은 180°로 시공하여야 하며, 특히 대구경관에서는 지반의 영향이 더욱 중요한 것으로 나타났다. 따라서 GRP의 안전성을 확보하기 위해서는 시공과정에서 되메움토에 대한 다짐도, 상대밀도, 흙의 종류에 대한 세부적인 규정과 관리가 필요하며, 특히, 헌치부에 대한 시공관리가 이루어져야 할 것으로 판단된다.

전 세계적으로 건설폐기물에 의한 환경문제에 대한 관심이 증가하고 있다. 이에 따라 건설재료들에 대한 재활용방안 에 대한 연구가 많이 진행되고 있다. GFRP는 최근 구조물의 보강에 많이 사용되는 건설 재료이다. 본 연구에는 GFRP를 분쇄하 여 만든 재활용 GFRP파우더(RGP)의 잔골재 대체 가능성을 검토하고자 하였다. RGP는 GFRP의 제작 시 발생되는 GFRP 잉여물을 분쇄하여 사용하였다. RGP의 잔골재 치환율을 20%, 40% 60% 80%로 설정하였다. RGP가 혼합된 시멘트 모르타르의 재료 성능을 검토하기 위하여 압축강도, 쪼갬인장강도 및 휨 강도를 측정하였다. 실험결과, RGP의 혼입으로 시멘트 모르타르의 기초물성이 증가하는 경향이 나타났다. 본 연구결과는 장기적으로 GFRP의 건설재료로의 재활용을 위한 기초자료로 활용이 가능할 것으로 판단된다.

The fatigue characteristics of glass fiber reinforced plastic (GFRP) composites were studied under repeated loads using the finite element method (FEM). To realize the material characteristics of GFRP composites, Digimat, a mean-field homogenization tool, was employed. Additionally, the micro-structures and material models of GFRP composites were defined with it to predict the fatigue behavior of composites more realistically. Specifically, the fatigue characteristics of polybutylene terephthalate with short fiber fractions of 30wt% were investigated with respect to fiber orientation, stress ratio, and thickness. The injection analysis was conducted using Moldflow software to obtain the information on fiber orientations. It was mapped over FEM concerned with fatigue specimens. LS-DYNA, a typical finite element commercial software, was used in the coupled analysis of Digimat to calculate the stress amplitude of composites. FEMFAT software consisting of various numerical material models was used to predict the fatigue life. The results of coupled analysis of linear and nonlinear material models of Digimat were analyzed to identify the fatigue characteristics of GFRP composites using FEMFAT. Neuber’s rule was applied to the linear material model to analyze the fatigue behavior in LCF regimen. Additionally, to evaluate the morphological and mechanical structure of GFRP composites, the coupled and fatigue analysis were conducted in terms of thickness.

유한요소법(finite element method)은 다양한 분야에서 재료의 역학적 거동을 더욱더 현실적으로 해석하고 예측하는 방법으로 다양한 분야의 제품 개발에 적용되고 있다. 하지만 섬유배향과 변형률 속도가 역학적 특성에 영향을 미치는 유리섬유 강화 플라스틱 복합재료에 관한 수치해석을 이용한 접근 방법은 현재까지 다소 어려움이 있다. 본 연구의 목적은 고분자, 고무, 금속 등과 같은 다양한 복합재료를 위한 선형, 비선형 다중스케일 재료 모델링 프로그램인 Digimat의 수치해석 재료 모델을 활용하여 유리섬유 강화 플라스틱 복합재료의 역학적 특성을 정의하고 검증하는 것에 있다. 또한 이를 통해 좀더 현실 적으로 고분자 복합재료의 거동을 예측하고자 한다. 이를 위해 다양한 고분자 중 30wt%의 단섬유 질량 비율을 갖는 폴리부 틸렌 텔레프탈레이트(polybutylene terephthalate, PBT)의 섬유배향과 변형률 속도에 따른 인장 특성을 참고문헌을 통해 조사하였다. 또한 Moldflow 프로그램을 사용한 사출해석을 통해 유리섬유 배향 정보를 계산하였으며 이를 매핑(mapping) 과 정을 통해 유한요소 인장 시편 모델에 전달하였다. 대표적인 유한요소 상용 프로그램 중 하나인 LS-DYNA는 유리섬유 배향과 변형률 속도에 따른 복합재료의 인장 특성을 연구하기 위해 Digimat과의 연성해석(coupled analysis)에 활용되었다. 그리고 유리섬유 강화 플라스틱 복합재료를 해석하기 위한 LS-DYNA의 다양한 비등방성(anisotropic) 재료 모델들의 장단점을 서로 비교하고 평가하였다.

Recently, there is an increasing the pavement distresses such as rutting with an increase in heavy vehicles on the road in Mongolia. Rutting is the longitudinal depression in the wheel path in asphalt pavements and it causes a hydroplaning and severe safety concern for users. This study aims to develop paving material that can prevent rutting on the road pavement by improving the durability of the asphalt mixture in Mongolia. Therefore, this study was carried out using the technique of reinforcing the material by adding fibers to conventional asphalt mixture. Fibers have been used to reinforce various materials for many decades in various parts of the world. It is generally understood that asphalt is strong in compression and weak in tension. Adding fibers with high tensile strength can help increase the strength of a mixture[1]. A mixture of glass fibers was used in this study to evaluate the performance characteristics. In coordination with the City of Ulaanbaatar, The test section selected in this study was Peace Avenue in Ulaanbaatar. The test section was a bus lane with severe rutting by heavy vehicles. The designated road test section performed cutting and overlay using five asphalt mixtures: Glass Fiber-reinforced Asphalt, Hot Mix Asphalt(10mm, 19mm), Polymer Modify Asphalt(2 types). The performance survey was conducted after the summer. As a result, No noticeable cracks were observed in glass-reinforced mixture section and the rut-depth of the glass-reinforced mixture is lower than other mixtures[2].

Recently, Cambodia has been investing a lot of money in the construction and maintenance of roads, which are social infrastructures. However, damage to the existing pavement is accelerating due to the old age of the road pavement, poor drainage facilities and increase in heavy traffic. To solve this problem, a fundamental solution such as a high-performance asphalt mixture is required to extend the life of road pavement. In this study, a high performance glass fiber reinforced asphalt mixture developed in Korea was applied to Cambodia. Prior to field application, Marshall stability tests were performed on glass fiber reinforced asphalt mixtures, SBS modified asphalt mixtures and asphalt mixtures commonly used in Cambodia. The Marshall stability test showed that the glass fiber reinforced asphalt mixture and the SBS modified asphalt mixture had the same strength (about 1.3 times higher strength than the usual asphalt mixture). In addition, the test construction was carried out on the National Highway 2 of Cambodia for the evaluation of the performance of the three mixtures. In the future, the long-term performance evaluation of each mixture will be conducted through follow-up survey of the test construction area.

In order to improve the durability of the asphalt pavement, the glass fiber reinforced asphalt which reinforces the aggregate and the binder in three - dimensional form by adding glass fiber to the asphalt mixture has been studied and the durability improvement effect of the asphalt pavement has been confirmed. Porous pavement has been increasingly applied due to reduced traffic accidents and noise reduction, but durability problems such as aggregate stripping and pot-hole are emerging. This study evaluated the durability enhancement effect by adding glass fiber to the porous mixture. The cantabro loss ratio and the indirect tensile strength test were performed to evaluate the performance of the glass fiber reinforced porous mixture. The glass fibers were added to the mixture using PG76-22 and PG64-22 binder and not to the mixture using PG82-22 binder. The mixture using the PG76-22 binder was added 1.4% (PEGS 0.6%, Micro PPGF 0.2%, Macro PPGF 0.6%) glass fiber based on the weight of the mixture. The mixture using the PG64-22 binder was added 1.4% (PEGS 0.6%, Micro PPGF 0.2%, Macro PPGF 0.6%) and 2.1% %(PEGS 0.9%, Micro PPGF 0.3%, Macro PPGF 0.9%)glass fibers by weight of the mixture. The glass fibers were used at the same ratio as that applied to the conventional asphalt mixture test. As a result of the cantabro loss rate test, the mixture using the PG82-22 binder showed a loss rate of 10.7% at 20 ℃ and 22.4% at -20 ℃. The mixture using PG76-22 binder and 1.4% glass fiber showed a loss ratio of 13.2% at 20 ℃ and 26.7% at -20 ℃. The mixture using PG64-22 binder and 1.4% glass fiber showed a loss rate of 12.5% at 20 ℃ and 35.9% at -20 ℃. The mixture using PG64-22 binder and 2.1% glass fiber showed a loss rate of 11.9% at 20 ℃ and 26.6% at -20 ℃. The three mixtures (using of PG82-22 binder, PG76-22 binder + 1.4% glass fiber and PG64-22 binder + 2.1% glass fiber) satisfied quality standard of Ministry of Land, Infrastructure and Transport. As a result of the indirect tensile strength test, the mixture using the PG82-22 binder showed 0.73 N/㎟. The mixture using PG76-22 binder and 1.4% glass fiber showed 0.88 N/㎟. The mixture using PG64-22 binder and 1.4% glass fiber showed 0.62 N/㎟. The mixture using PG64-22 binder and 2.1% glass fiber showed 0.74 N/㎟. In this study, the durability enhancement effect was confirmed by adding glass fiber to the drainage mixture. We will do further research to confirm the optimal combination of glass fibers.

The pultruded fiber reinforced polymer plastic (PFRP) is one of the most actively studied composite materials for the structural member in construction industries. In domestic design process, the PFRP member is designed as an isotropic material having only longitudinal material properties for simplicity, because it is too complex to consider orthotrophy of PFRP perfectly. In this study, three cases of buckling analysis of PFRP plate is conducted theoretically and numerically. First, the PFRP plate is considered as an orthotropic material. Second, the PFRP plate is considered as an isotropic plate having only longitudinal material properties. Third, the PFRP plate is considered as an isotropic plate having geometric mean of longitudinal and transverse material properties. As a result of buckling analysis, a buckling strength of PFRP plate as an isotropic plate having only longitudinal material properties is about 2.21 times larger than that of PFRP plate analyzed as an orthotropic plate. On the other hand, a buckling strength of PFRP plate as an isotropic plate having geometric mean material properties is about 1.19 times larger than that of PFRP plate analyzed as an orthotropic plate. In conclusion, the safety factor of 3 used in domestic design process of PFRP member is no longer applicable due to overestimation of buckling strength of PFRP member which leads to nonconservative design.

PURPOSES: This study evaluated the field applicability and laboratory performance of glass fiber-reinforced asphalt (GFRA) mixtures. METHODS : The general hot-mix asphalt (HMA) and GFRA mixtures were paved in five sites, including three national highways, one express highway, and an arterial road, to evaluate field applicability and durability. The plant mixing and construction method for the GFRA were similar to those for the general HMA. The lab performances of the field samples were relatively compared through the mechanical measures from the Marshall stability, indirect tensile strength, and dynamic stability. The field performance was surveyed after a year. RESULTS : The lab tests verified the superior lab performances of the GFRA compared to the general HMA. The Marshall stability of the GFRA increased for about 128% of the general HMA. The indirect tensile strength of the GFRA was 115% greater than that of the general HMA. The dynamic stability of the GFRA resulted in 16,180 reps/mm, which indicated that high rut resistance may be expected. No noticeable defects, such as cracks or deformation, were observed for the GFRA sections after a year. CONCLUSIONS: The lab tests and field survey for the five GFRA sites resulted in superior performances compared to the general HMA. The relatively low-cost GFRA, which required no pre-processing procedures, such as polymer modification, may be a promising alternative to the polymer-modified asphalt mixtures. The long-term performance will be verified by the superior field durability of the GFRA in the near future.

Pipe line for the water supply and/or drainage is one of the most important life lines which is usually suffered from the damage due to exterior load induced deformation and due to the lack of support resistance provided by the surrounding soil. GFRP (Glass Fiber Reinforced Polymer Plastic) pipes are generally thinner, lighter, but stronger than the existing concrete or steel pipes, and it is excellent in stiffness/strength per unit weight. In this study, we present the result of field test for buried RPMP (Reinforced Polymer Mortar Pipe) and RTRP (Reinforced Thermosetting Resin Pipe) pipes with 2,400mm diameter. The vertical and horizontal ring deflections are measured for 387 days. The ring deflection of RPMP and RTRP measured by the field test is compared with the ring deflection limitation (5%) according to ASTM D 2412.

For the artistic column used by Glass Fiber Reinforced Plastic(GFRP), the connection of steel with GFRP were needed. Due to the fabricating characteristics of hand laminating, GFRP surfaces had to be connected. Because there were no existed data of these connection, experimental study has to be followed so that the structural strength and buckling mode could be investigated. In this paper, therefore, the axial tests of steel with GFRP were performed. The connection of GFRP's surfaces could be also tested as well. As a result, it could be figured out that the strength of these connections were determined by the adhesive strength.

Concrete and steel has been used as the main material of structure from building and drainage pipe. However, many problems such as corrosion and rupture had occurred in the Water Supply and the Sewer System. Additionally, the government has invested big budget to Deteriorated pipe replacement and maintenance. Replacement of existing pipelines in order to solve these problems, GFRP pipe(glass fiber composite material pipes) is aspiring to replace the tube. GFRP has high strength, restore performance, durable and lightweight properties. However, high strength GFRP pipe is weak in buckling problem. This study is to analysis Optimization Design models for resisting bucking problem of GFRP pipes. Thus, various tests Changed the angle of Glass-Fiber-Reinforced Layer and the resin content of resin-mortar were performed for GFRP pipes to estimate material characteristics of GFRP in this study. Buckling analysis of composite structures under external uniform pressure was performed with the results obtained through test.

휨 거동 및 전단부의 전단거동으로 인한 철근상세 및 사용되어지는 철근의 과다로 인하여 취성파괴의 양상이 발생 하고 있다. 이에 본 실험에서는 유리섬유망을 이용하여 철근과의 휨 및 변위 거동을 통하여 무보강철근과 유리섬유망의 ply 수에 따른 휨거동 실험을 통하여 균열을 살펴보고서 향후 휨 거동에 적정한 유리섬유망의 철근의 배치겹수에 대한 사용량을 검토하고자 한다.