• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.1
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• pp.42-45
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• 2008

It has been reported that FRP (fiber reinforced plastic) can be recycled by separating into layers instead of crushing into powder. F-fiber obtained from roving layer separated from FRP, has bigger tensile strength than the bundle of glass fibers of which FRP was made (more than 90%). SEM image of F-fiber shows the presence of some resin. Under the proposition of usage of F-fiber in the concrete material, tensile strength is examined after soaking in a basic solution (NaOH+KOH). The reaction mechanism of strength loss may be considered as an attack of hydroxide ion ($OH^-$) on a chemical bond of Si-O-Si of glass fiber. The simulation graph of the strength loss data implies certain reaction mechanism. While in the early stage kinetically controlled reaction results in a fast drop of tensile strength, after 30 days dispersion rate of hydroxide ion plays a major role in strength loss. This result is similar to the one for the AR glass. An extrapolation of the graph would make an assumption about the lift time of F-fiber possible.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.1
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• pp.29-34
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• 2009

For several decades, many researchers have been involved in developing recycling methods for FRP boats. There are four basic classes of recycling covered in the literature. Despite of environmental problems(safety hazards), mechanical recycling of FRP boats, which involves shredding and grinding of the scrap FRP, is one of the simpler and more technically proven methods than incineration, reclamation or chemical ones. Because FRP is made up of reinforced fiber glass, it is very difficult to break into pieces. It also leads to secondary problem in recycling process, such as air pollution and unacceptable shredding noise level. Another serious problem of mechanical FRP recycling is very limited reusable applications for the residue. This study is to propose a new and efficient method which is more wide range applications and environment friendly waste FRP regenerating system. New system is added with the cyclone sorting machine for airborne pollutions and modified cutting system for several glass fiber chips sizes. It also has shown the FRP chip fiber-reinforced concrete and fiber-reinforced secondary concrete applications with the waste FRP boat to be more eligible than existing recycling method.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.4
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• pp.19-27
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• 2011

In this paper, we present a part of results to develop new type hybrid FRP-concrete composite pile (i.e., concrete filled fiber reinforced plastic circular tubes, hybrid CFFT, HCFFT). The purpose of this paper is to evaluate compressive loading capacity through compressive strength test. Before compressive strength test of HCFFT, we investigated mechanical properties of pultruded fiber reinforced plastic (PFRP) and filament winding fiber reinforced plastic (FFRP). For estimating the compressive strength of HCFFT, uni-axial compression strength tests of HCFFT compression members were conducted. The test variables are compressive strengths of concrete and thickness of FFRP. In addition, uni-axial compression strength tests of concrete filled fiber reinforced plastic circular tube (CFFT) except PFRP members were conducted. The test variable in the test is thickness of FFRP. From the test result, the compressive strength of the HCFFT in larger than compressive strength of CFFT as much as 47%. It can be observed that the uni-axial compressive strength of the HCFFT increased if the concrete strength and the thickness of exterior filament winding FRP tube increased. In addition, the finite element analysis result is compared with the experimental result. The difference between the experimental and FEM results is in the range of 0.14% to 17.95%.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.3
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• pp.247-254
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• 2010

Due to lightweight and high durability of glass-fiber reinforced polyester (GFRP) materials, they are promising alternatives to conventional construction materials such as steel, concrete and wood. As good application examples of GFRP materials, several types of temporary arch bridges were suggested and verified by finite element analyses in our previous study where snap-fit GFRP decks were applied. In this paper, we conduct a structural performance test to verify safety and serviceability of the temporary arch bridge, where snap-fit GFRP decks are assembled by bolts. The structural problems occurred in this test are also discussed and improvement of temporary arch bridges is suggested to resolve the occurred structural problems.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.21 no.3
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• pp.217-223
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• 2008

Glass-fiber reinforced polyester (GFRP) composite material is a promising alternative to existing construction materials such as steel, concrete and wood due to light weight and high durability of GFRP composite material. If a temporary arch bridge is built by GFRP composite deck, rapid construction of the bridge and reuse of the GFRP composite deck are possible. In this paper, we develop a type of temporary arch bridges that can be built by easy assembling of GFRP composite decks. For this purpose, several possible types of temporary arch bridges are suggested and verified by finite element analysis.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.2
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• pp.26-33
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• 2011

Recently, the use of buried glass fiber reinforced plastic (GRP) pipes is widespread and ever increasing trend in the industry. GRP pipes are attractive for use in harsh environments, such as for the collection and transmission of liquids which are abrasive and/or corrosive. The structural behavior of a GRP pipes buried under the ground is different from that of a rigid one made of concrete or clay, for example. A GRP pipe buried under the ground is deflected circumferentially by several percent and the stresses in the pipe are mainly compressive stresses. A GRP pipes has been introduced by a number of manufacturers for selection and used by underground pipeline designers. In all cases, the modified Spangler's equation is recommended by these manufacturers for predicting the ring deflection of these pipes under dead and live loads. In this paper, the ring deflection of buried GRP pipe is evaluated and discussed based on the result of analytical investigation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.4245-4252
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• 2015

In this study, an experiment which utilized glass fiber reinforced polymer(GFRP) plank as the permanent formwork of cast-in-place high strength concrete structures was performed. The GFRP plank currently being produced has smooth surface so that it causes problems in behavior with concrete. Therefore, this research analyzed the flexure/shear failure behavior of composite beams, which used GFRP plank as its permanent formwork and has short shear span ratio, by setting the sand coated at GFRP bottom surface, the perforation and interval of the GFRP plank web, and the width of the top flange as the experimental variables. As a result of the experiments for effectiveness of sand attachment in case of not perforated web, approximately 47% higher ultimate load value was obtained when the sand was coated than not coated case and bending/shear failure mode was observed. For effectiveness of perforation and interval of gap, approximately 24% higher maximum load value was seen when interval of the perforation gap was short and the fine aggregate was not coated, and approximately 25% lower value was observed when the perforation gap was not dense on the coated specimen. For effectiveness of top flange breadth, the ultimate load value was approximately 17% higher in case of 40mm than 20mm width.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.1
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• pp.50-54
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• 2008

There are several basic classes of recycling methods for FRP boats. The main one is 'Mechanical recycling' which involves shredding and grinding of the scrap FRP in a new product. That is one of the simpler and more technically proven methods. It recently has been reported that FRP can be recycled by separating into layers instead of crushing into powder. Many researchers should be more interested in these mechanical recycling for the eligibility. Nevertheless, because resins is very useful renewable energy, most of waste FRP regenerating methods depend on incineration (reclamation) or thermal recycling (pyrolysis). FRP is made up of laminated glass- fiber (roving cloth layer) which is also very unlikely to break into each layer. If there is an extracting method which is efficient and environment friendly removing glass fiber from waste FRP, it should also solve the another urgent problem. Laminated glass-fiber which is very limited renewable, is a serious barrier to wast FRP boat regenerating. This study is to propose a new extracting method which is efficient and environment friendly waste FRP regenerating system. And it should be applied to renewable energy applications with the waste resins of FRP. Also recycling glass fiber obtained by the separation of the roving layer from waste FRP will be consider to be useful for concrete products or structures.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.11
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• pp.137-146
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• 2019

Recently, the Near-Surface-Mounting method using Fiber reinforced polymer (FRP) has been developed and applied to the reinforcement of many concrete structural members. However, as a part of the fire resistance design, there is a lack of research related to fire insulation for the areas reinforced with FRP. In case of NSM reinforcement, there is a difference in the transferred temperature from the external surface to the groove corresponding to the location of the groove where the FRP is embedded, and the effect of this should be reflected in the fireproof insulation design. Therefore, in this study, after forming grooves for surface embedding in concrete blocks, fireproof insulation reinforcement was performed using Calcium Silicate (CS) fireproof board and an experiment to evaluate the temperature transfer was performed. By observing the temperature at these groove positions, the reduction of temperature transfer according to fireproof insulation detail was studied. As a result, when the NSM-FRP is properly fire-insulated using the CS-based fireproof board, the epoxy inside the groove does not reach its glass transition temperature until the external temperature reaches $800^{\circ}C$.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.1
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• pp.9-16
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• 2009

For reinforced concrete members, bond strength is one of the important factors between the two materials: the concrete and the reinforcing element. The bond strength of Aramid Fiber Reinforced Polymer (AFRP) rebar was tested using the pull-out method. Presented were comparison results of the bond strength between AFRP rebar and deformed steel bars from the test. Embedded lengths and diameters of the rebar were taken into account as parameters. The bond stress-slip responses and failure modes of AFRP rebar were evaluated. It was found that the bond stress-slip responses of AFRP rebar were similar to those of deformed steel bars. As the diameter of rebar increased, the pull-out load increased. In addition, it was shown that the bond strength of an AFRP rebar was approximately 54% compared with that of a deformed steel bar.