• International Journal of Precision Engineering and Manufacturing
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• v.9 no.4
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• pp.71-73
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• 2008

The development of polymer/inorganic nanocomposites has attracted a great deal of interest due to the improved hybrid properties derived from the two different components. Various nanoscale fillers have been used to enhance polymer mechanical and thermal properties, such as toughness, stiffness, and heat resistance. The effects of the filler on the final properties of the nanocomposites are highly dependent on the filler shape, particle size, aggregate size, surface characteristics, polymer/inorganic interactions, and degree of dispersion. In this paper, we describe the influence of different $CaCO_3$ dispersion methods on the thermal properties of polyethylene terephthalate (PET)/$CaCO_3$ composites: i.e., the adsorption of $CaCO_3$ on the modified PET surface, and the hydrophobic modification of the hydrophilic $CaCO_3$ surface. We prepared PET/$CaCO_3$ nanocomposites using a twin-screw extruder, and investigated their thermal properties and morphology.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1139-1144
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• 2000

Recent advance in material technology has accelerated the development of high strength concrete using lightweight artificial aggregates. The lightweight concrete has many advantages that the reduction of dead lads and the increase in load capacity can ofter. In this study, lightweight polymer concrete using unsaturated polyester resin and lightweight aggregate were prepared and tested for testing the physical and the mechanical properties. The compressive strengths of lightweight polymer concretes with specific gravities from 1.32 to 1.78 were compressive strength of 250 to 470 $kgf/cm^2$ and flexural strengths were measured to be in the range of a third to a quarter of compressive strength

• Proceedings of the Korea Concrete Institute Conference
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• 1991.10a
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• pp.93-98
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• 1991

Polymer-Impregnated Concrete(PIC) can be considered composite material of concrete and polymer and has superior properties compared to conventional cement concrete, such as strength, stiffness, toughness, durability, water-proofing, chemical resistance. However, so far, the usage of PIC has been limited to repairing materials and non-structural applications, due to the lack of the design criteria and the analytical model to determine structural behavior. The objective of this study is to define the stress-strain response and strength characteristics of PIC in uniaxial and various biaxial compressive loading. On the bases of experimental results, general stress-strain relation, biaxial failure envelope and strength evaluation formular of PIC made with normal aggregate and methylmethacrylate(MMA) are proposed.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.5
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• pp.104-105
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• 1999

This study was performend to examine Poisson's ration of polymer-modified asphalt concrete due to temperature variatino . Asphalt binder used in this study was an AC85-100, penetration grade of 85-100, and polymer for modifying asphalt were domestic LDPE(Low-density polyethylene) and SBS(Styrene-butadiene-styrene). Aggregate was a crushed gneiss which was most widely used in the middle part of Korea. Using these materias, asphalt mixture slab(340mm$\times$240mm$\times$80mm) with optimum asphalt content from mix design was made and cut into square pillar (80mm$\times$80mm$\times$160mm). Poisson's ration was measured in various temperture (-15$^{\circ}C$, -1$0^{\circ}C$, -5$^{\circ}C$,$0^{\circ}C$,5$^{\circ}C$,1$0^{\circ}C$ and 2$0^{\circ}C$) under the load of one axis repeated compression mode. Poisson's ration of normal asphalt polymer modified asphalt mixtures in normal temperatures. This indicated that AP mixture was more susceptible to temperature effects. From regression aalysis of experimental results, the difference of Poisson's ration between normal and low temperature showed that polymer modified asphalt mixture were lower than AP mixture except for SBS modified asplat mixture.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6565-6574
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• 2013

Precast concrete blocks are used mainly for score protection, slope protection and riverbed structure protection, etc. Because these concrete blocks are exposed to water or wetting environments, the steel rebar used as reinforcements in concrete blocks can corrode easily. Corrosion of the steel rebar tends to reduce the performance and service life of the concrete blocks. In this study, Glass Fiber Reinforced Polymer(GFRP) rebar, which does not corrode, was applied instead of a steel rebar to prevent performance degradation of the blocks. Recycled concrete aggregate and high early strength cement(HESC) were used in the concrete mix for field applicability. The experiment results showed that the workability and form removal strength of the recycled aggregate concrete using HESC showed comparable results to normal concrete and the compressive strength at 28 days increased by about 18% compared to normal concrete. The load resistance capacity of the recycled aggregate concrete blocks reinforced with a GFRP rebar increased by approximately 10~30% compared to common concrete block.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.261-266
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• 2003

This study is to investigate the heating value and noxious gases generation such as CO, NO and $SO_2$ known as dangerous gas for human from specimen made of cement and lightweight aggregate. The most quanity of CO gas is generated in EPS(Expanded Poly Styrene), core of commercial sandwich panel. Although specimens mainly composed of cement discharged the relatively less CO gas than organic core such as EPS, specimens which SBR was added discharged the very much amount of CO gas similar to EPS and especially, specimens including foaming agent, gas foaming agent or redipersible powder of VA/VeoVa showed the good properties in the generation of CO gas. From the standpoint of the generation of NO and $SO_2$ gas, both the core of commercial sandwich panel such as EPS, Glass wool and specimens made with polymer dispersion such as St/BA and SBR discharge the very much amount of NO and $SO_2$ gas in comparison of the other specimens. From this study, it was confirmed that organic materials such as core of commercial sandwich panel dischared much more noxious gas than specimens composed of cement and inorganic lightweight aggregate.

• Steel and Composite Structures
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• v.43 no.2
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• pp.257-270
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• 2022

Recycled aggregate concrete (RAC) is rarely used in load-carrying structural members. To widen its structural application, the compressive behavior of a promising type of composite column, steel-fiber reinforced polymer (FRP) double-tube confined RAC column, has been experimentally and analytically investigated in this study. The objectives are the different performance of such columns from their counterparts using natural aggregate concrete (NAC) and the different mechanisms of the double-tube and single-tube confined concrete. The single-tube confined concrete refers to that in concrete-filled steel tubular (CFST) columns and concrete-filled FRP tubular (CFFT) columns. The test results showed that the use of recycled coarse aggregates (RCA) affected the axial load-strain response in terms of deformation capacity but such effect could be eliminated with the increasing confinement. The composite effect can be triggered by the double confinement of the steel and carbon FRP (CFRP) tubes but not by the steel and polyethylene terephthalate (PET) FRP tubes. The proposed analysis-oriented stress-strain model is capable to capture the load-deformation history of such steel-FRP double-tube confined concrete columns under axial compression.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.218-219
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• 2014

The purpose of this study is to develop eco-friendly internal material of acrylic emulsion mortars using light-weight aggregate carrier which contains pyroligneous liquid. Four types of light-weight aggregates (vermiculite, perlite, charcoal, zeolite) that are widely used in building materials are selected and the properties such as adhesion, water absorption coefficient, antibiosis, crack and impact resistance are evaluated in accordance with KS F 4715. As a result, the properties of acrylic emulsion mortars using light-weight aggregate carrier are satisfied with KS requirements. The antibiosis is improved with increasing zeolite light-weight carrier content.

• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.5
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• pp.45-54
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• 2014

This study was performed to evaluate compressive strength, flexural strength, static modulus of elasticity, stress-strain ratio and durability of abrasion on EVA concrete reinforced steel fiber (SF) in order to use hydraulic structures, underground utilities, offshore structures and structures being applied soil contaminated area. It is used ordinary portland cement, crushed coarse aggregate, nature fine aggregate, EVA redispersible polymer powder, superplasticizer and deforming agent to find optimum mix design of EVA concrete reinforced steel fiber. EVA concrete reinforced SF was effected on the improvement of mechanical properties and durability of abrasion.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1127-1132
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• 2000

The purpose of this study is to investigate the utilization of recycled fine aggregates as a material to apply to concrete curbs. This study also intends to improve the quality of recycling aggregates by adding an excellent polyester resin for the improvement of durability, anti-corrosiveness, and strength. The experimental mixing proportion was planned to acquire optimum workability and filling capability of resin mortar mixed with the recycled fine aggregate. The curbs products made for test have four type cross sections. Their flexible fracture load is 1,918~6,883kgf and their weight is 15.31~31.61kg.