• Structural Engineering and Mechanics
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• v.82 no.2
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• pp.163-172
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• 2022

Zinc-rich epoxy (ZRE) is used to overcome corrosion problems in reinforced concrete (RC) beams and coat steel rebars to protect them from humidity and chlorides. An extra coating layer of Sikadur-31 epoxy (SDE) is utilised to increase bond strength because the use of ZRE reduces the bond strength between concrete and steel rebars. However, the low melting point of SDE indicates that concrete specimens are vulnerable to fire. An experimental investigation on flexural performance of RC beams incorporating ZRE-SDE coating of steel rebars that were destroyed by fire is performed in this study. Twenty beams of five concrete mixes with different cementitious contents were tested to compare fire exposure for coated and uncoated rebars of the same beams at room temperature and determine the optimal cementitious content. Scanning electron microscopy (SEM) was also applied to investigate characteristics of fired mixture samples. Results showed that the use of SDE-ZRE at room temperature improves flexural strengths of the five mixes compared with uncoated rebars with percentages ranging from 8.5% to 12.3%. All beams with SDE-ZRE lost approximately 50% of their flexural strength due to firing. Moreover, the mix incorporating SF (silica fume) of 15% and cement content of 400 kg/m³ introduces optimum behaviour compared with other mixes. All results were supported and verified by the SEM analysis and compressive strength of cubic specimens of the same mixes.

• Journal of Adhesion and Interface
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• v.2 no.2
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• pp.1-10
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• 2001

Silica for Epoxy Molding Compound (EMC) was coated via plasma-polymerization with RF plasma (13.56 MHz) as a function of treatment time, power and pressure. 1,3-diaminopropane, allylamine, pyrrole, 1,2-epoxy-5-hexene, allylmercaptan or allylalcohol were utilized for plasma polymerization coating and adhesion of coated silica was evaluated by measuring flexural strength. CTE and water absorption of EMC were also measured, and fracture surface of flexural specimen was analyzed by SEM in order to elucidate the failure mode. The plasma polymer coated silica was analyzed by FT-IR and reactivity of plasma polymer coating with epoxy resin was evaluated with DSC in order to investigate the adhesion mechanism. The EMC prepared from the silica coated with 1,3-diaminopropane or allylamine exhibited high flexural strength, low CTE, and low water absorption compared with the control sample, and also exhibited 100% cohesive failure mode. These results can be attributed to the chemical reaction between the functional groups in the plasma polymer coating and epoxy resin, and also consistent with the results from FT-IR and DSC analysis.

• Corrosion Science and Technology
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• v.13 no.5
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• pp.186-194
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• 2014

Establishment of adhesion strength measurement procedure for marine epoxy coatings was conducted in order to ensure reliability of the test results. It was found that (1) the increase in thickness of the substrates would induce increase of pull-off strength. Especially, the increase in adhesion strength with the substrate thickness increment was attributed to the transition of stress mode to the pure tensile mode excluding bending effect. (2) The longer curing time, the higher pull-off strength. It may be due to higher cross-linking density of the coating (3) The pull-off strength increases as coating thickness increases due to the diminishment of bending effect (4) The longer drying time after water immersion, the higher pull-off strength. It may be due to the evaporation of water molecule at the coating-substrate interface.

• Special Issue of the Society of Naval Architects of Korea
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• 2013.12a
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• pp.66-72
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• 2013

The demand for an ice class ship is rising expected to rise according to the increase of energy consumption and the opening of arctic sea routes. Ice class ship should be designed to cope with the severe environmental conditions of arctic sea such as a high mechanical impact and abrasion damage, caused by pack ice, ice bergs and low temperature. The ice class ship hulls are coated with an anti-abrasion and low friction coating such as a solvent free epoxy or high solid-volume epoxy. These coatings require two-component heating pump and a high grade surface preparation. In this study, the coating performances for the arctic vessels, such as puncture absorbed energy, abrasive wear loss, friction coefficients and impact absorbed energy were evaluated. Based on this study, a proper coating performance specification for the arctic vessels was proposed and coating selection guideline in terms of coating performance and workability was also established.

• Polymer(Korea)
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• v.38 no.3
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• pp.371-377
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• 2014

The effect of modification conditions on the physical properties of polydimethyl siloxane modified epoxy (PDMSME) was investigated. The number of ring opened epoxy attached to polydimethylsiloxane (PDMS) by silane coupling agent affected the physical properties of undercoating materials. The flexibility of thin coating was enhanced by PDMSME and the increase of ring opened epoxy attached to PDMS resulted in the increase of hardness by the crosslinking in the present with moisture. The higher molecular weight of PDMS caused the lowering of hardness while the surface contact angle increased due to the high silicone content in PDMS. The viscosity of silicone modified epoxy coating materials decreased with increasing of molecular weight of PDMS due to the lowering of entanglement of PDMSME molecules by acetone solvent and consequently, the smooth undercoated surface was obtained.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.211-216
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• 2003

Coated bars are protecting reinforcing bars from corrosion and enhancing durabilities of reinforced concrete structures are tested to evaluate corrosion protection properties. Tests are performed based on the relevant standards of ACI and ASTM, such as chemical resistance, salt water spray, salt crack test and chloride permeability test with the main variable of the coating thickness. Three type materials are tested by Polyethylene, epoxy and bare bar. Test results show good chemical protection property and chloride permeability. Polyethylene coated bar is good coating material than any other materials.

• Journal of the Korean Society of Marine Environment & Safety
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• v.5 no.2
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• pp.15-26
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• 1999

The marine structures with sea water cooling system always expose to the oceanic atmosphere. Therefore, the protection of the equipments is very important. To investigate the effectiveness of advanced composite materials for the application in offshore environments, the tensile test, hardness test, undercutting property test, permeance test and the friction and wear test were carried out by using various applicable coating materials. The main results obtained can be summarized as follows; 1. The micro-hardness of the Archcoat 502B showed the highest value. 2. The coefficient of friction of the Rigspray coating at the speed of 2.21m/sec showed the lowest value, and that of the Archcoat 502B coating at 1.08m/sec and 0.18m/sec indicated the lowest values. 3. The wear mass at the speed of 0.18m/sec and 1.08m/sec in dry condition showed the smallest values. 4. The Archcoat 502B coating is fitted to the dynamic instruments in the range of low speed and middle speed. Rigspray coating is fitted to the dynamic instruments in the range of high speed. 5. The wear mass of five kinds of coating materials at the range of low speed was very small, and those of the Archcoat S02B, Archcoat 402B and Rigspray coating at high speed range were quitely smaller than those of the Modified Epoxy and Tar Epoxy.

• International Journal of Concrete Structures and Materials
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• v.2 no.1
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• pp.21-25
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• 2008

Surface treatments act as a barrier between the environment and the concrete, preventing or retarding the entry of harmful substances and cutting off the transportation path into concrete. The effectiveness of a surface protection preventing the permeation depends on how close and strongly connected are the resin molecules. This work intends to contribute to a better understanding of the performance of protected concrete in chemically aggressive environments, by presenting results of ion diffusion and resistance to aggressive solutions of several hydrophobic agents and coatings used to protect concrete. Three different types of surface protections were tested: silicone hydrophobic agent, acrylic and epoxy coatings. The obtained results indicate that the overall performance of epoxy resin was better than the other selected types of protections.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1887-1889
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• 2002

One of the most frequent sources of the accident is metal contaminant in GIS. This paper deals with the characteristics of breakdown voltage of metallic particles using electrodes of various epoxy coating thickness. As experimental results, breakdown voltage of the thickly coated electrode is higher than that of thinly coated electrode. It is considered that resistance of the epoxy coating impedes the development of pre-discharges in the gas.

• Journal of Korean Society on Water Environment
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• v.16 no.4
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• pp.469-477
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• 2000

Bisphenol-A (BPA), a known endocrine disruptor, is a main building block of epoxy resin which is widely used as a coating agent in residential water storage tanks. Therefore, BPA leaching from the epoxy resin may have adverse effects on human health. The possibility of BPA leaching from three epoxy resins were tested with a modified KS D 8502 method at 20, 50, 75 and $100^{\circ}C$ in deionized water and the specified test water, respectively. BPA leached to the test water was identified using GC-MS and quantified with GC-FID after a sequential extraction and concentration. The results showed that BPA leaching has occurred in all three samples tested. The quantify of BPA leaching from unit area of epoxy resin coating was in the range of $10.677{\sim}273.120{\mu}g/m^2$ for sample A, 29.737~1734.045 for sample B and 52.857~548.778 for sample C depending on the test temperature, respectively. In general, the amount of BPA leaching increased as the water temperature increases. This result implies a higher risk of BPA leaching to drinking water during a hot summer season. In addition, microbial growth, measured by colony forming units, in epoxy coated water tanks was higher than that in a stainless steel tank suggesting that compounds leaching from epoxy resin may support the growth of microorganisms in a residential water holding tank.