• Corrosion Science and Technology
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• v.7 no.2
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• pp.125-129
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• 2008

Results of corrosion testing for different grades of titanium, copper, zinc, alluminium alloys and steels after two years of outdoor exposure under humid tropical urban and marine conditions have been presented and discussed. Mass loss and corrosion product characteristics for the exposed specimens at Hanoi testing site with high humidity and Nhatrang marine stations (at 100 and 1,000 meters distances from sea) with different airborne salinities (35.9 and $90.0mg/m^2.d$ respectively) have been selected for investigation. From time dependence of the specimen mass loss and corrosion product characteristics, the strong influence of environmental parameters upon durability for the investigated metals and alloys has been demonstrated. Only titanium alloys show high resistance to the marine conditions. All the other specimens (copper, zinc, alluminium alloys and steels) have been underwent strong deterioration under influence of aerosol salinity. Results of corrosion products analysis have been also presented for characterization of environmental impact on the metal degradation processes.

• International Journal of Concrete Structures and Materials
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• v.8 no.3
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• pp.201-212
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• 2014

Sixteen reinforced concrete laboratory specimens were used to evaluate a number of corrosion prevention methods under an accelerated (6 months) testing program. The use of galvanic thermal sprayed zinc, galvanic embedded anodes, a tri-silane sealer, an acrylic coating, and an epoxy/polyurethane coating was evaluated. The specimens received various treatments prior to exposure to accelerated corrosion. The performance of the treatments was evaluated with respect to corrosion currents, chloride ingress, extent of cracking, severity of rust staining, and visual inspection of the reinforcing steel after the conclusion of testing and dissection. Results indicated that the tri-silane sealer, the conjoint use of galvanic thermal sprayed zinc and epoxy/polyurethane coating, the epoxy/polyurethane coating, and acrylic coating performed better than the other methods tested. Higher chloride concentrations were measured in the vicinity of embedded zinc anodes.

• Corrosion Science and Technology
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• v.16 no.5
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• pp.241-246
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• 2017

The comparative results of corrosion testing in humid tropical atmosphere in rural and coastal areas for hot dipped zinc coatings are presented below. The test was conducted in outdoor conditions over a period of five years. The mass loss and other performance characteristics of two types of zinc coatings were evaluated, analysed and discussed in relation to the climatic and environmental parameters. The corrosion rates of the coatings exposed to coastal conditions were about three times higher than the corrosion rates appreciated in rural conditions. The data demonstrates that the corrosion process obeys an equation of the form $M=At^n$, where M is the loss of metal and t is the time of exposure. A and n are constants which values depend on the environmental characteristics and the physicochemical behavior of the corrosion products respectively. Corrosion is strongly influenced by atmospheric time of wetness (TOW) and airborne salinity. The nature and composition of corrosion products are also considered. Simonkolleite, a major crystalline phase, was found in the zinc corrosion products exposed to coastal conditions, while zinc hydroxide and zinc hydrosulfate are easily found in rural settings.

• Journal of Environmental Health Sciences
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• v.33 no.1 s.94
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• pp.43-48
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• 2007

This study investigated the effects of pH, alkalinity, and chlorine ion which are important water quality impact factors to the corrosion in the simulated distribution system where the copper pipe is affixed. The result shows that pitting index was increased as the alkalinity and chloride ion increase in the distilled water, but there was no relation to pH. Actually the uniform corrosion rate was decreased as the pH increase with the laboratory tap water. In conclusion, it is necessary to control the pH which stands above minimum 7.5 to prevent pitting corrosion in the copper pipe. Consequently, comprehensive research about the effect of lime soda($Ca(OH)_2$) which was used as a coagulation additive in the water treatment plant to pipe corrosion must be accomplished additionally.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.739-742
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• 1999

A reinforcement corrosion prediction model was proposed using the results from accelerated testing and mathematical equation from the Fick's 2nd law for chloride-induced corrosion of reinforcement in concrete. The input data included the chloride concentration, mix characteristics of concrete, and environmental conditions. This model can be used to predict the chloride concentration pertaining to corrosion time and loading age for marine concrete structures. This model can also be used to predict the service life.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1117-1124
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• 2009

Under frame side sill of rolling stock structure is designed for preventing corrosion in order to meet mechanical requirements. However during long operation time more than 20 years, there are corrosion in the under frame side sill caused by environmental effect, vibration and etc. So, detection and evaluation of the corrosion ill the under frame nondestructive is one of important issues to extend their life time. Most of nondestructive methods are not easy to apply for detecting corrosion in the under frame side sill, since the under frame side sill consist of there layered with different material (stainless steel - stainless steel - mild steel) and each layer is connected by spot weld and plug weld. Fortunately, pulsed eddy current method claimed that it can be measured not only thickness change but also corrosion under their insulation layers. So, in this study, we have investigated performance of pulsed eddy current testing method by measuring thickness variation of fabricate of mock-up specimens. The investigation results obtained from mock-up specimens and the corrosion evaluation results of the aged rolling stocks will be presented.

• Journal of the Korean Institute of Gas
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• v.5 no.2 s.14
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• pp.14-21
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• 2001

In order to investigate the damage mechanism of the coupler transferring LPG, microstructural observation and chemical analysis of the couplers operated for the long time in the LPG stations and virgin 6/4 forged-brass corrosion-tested were conducted. Their microstructure was consisted of two phases that bright $\beta$ precipitates were irregularly dispersed in $\alpha$ matrix. The chemical compositions of oxide layer on the surface of the used coupler were composed of S, C, O, Al, Si, etc. as well as Cu and Zn. In environmental corrosion tests of both $10\%$ HCl and Mattsson solutions, no apparent deviations in mechanical impact strength of forged-brass was observed. While, in U-bend stress corrosion cracking specimen, some microcracks were observed.

• Geomechanics and Engineering
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• v.21 no.5
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• pp.423-432
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• 2020

Hydraulic conductivity is one of the engineering properties of soil. This study focusses on the influence of cement content on the hydraulic conductivity of cemented sand, which is investigated based on the results from numerical analysis and laboratory testing. For numerical analysis the cemented samples were scanned using X-ray Computed Tomography (CT) while laboratory testing was carried out using a triaxial setup. Numerical analysis enables us to simulate flow through the sample and provides insight to the microstructure. It quantifies the pore volume, proportion of interconnected voids and pore size distribution in both cemented and uncemented samples, which could be computed only through empirical equations in case of laboratory testing. With reduction in global voids, the interconnecting voids within the samples also reduce with cement content. Gamma cumulative distribution function is used to predict the percentage of voids lesser than a given pore volume. Finally, the results obtained from both numerical analysis and laboratory testing are compared.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.339-341
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• 2002

The remaining life of ACSR exposed to the atmosphere for a long period may rely on deterioration caused by environmental indices such as atmospheric corrosion, galvanic corrosion, crevice corrosion and fatigue corrosion. One of reduction of useful life in overhead transmission lines built on the ridge of mountain is often caused by forest fires. This paper deals with investigation of strength deterioration performance of ACSR due to fires through several testing and analyzing data for both tension load and material analysis. Test samples are ACSR $480[mm^2]$ conductors, which are artificially fired to regular durations. As a result, it can be verified that tension load of ACSR are reduced by increasing fro duration. Hence, it is obvious that ACSR due to forest fires may lead to mechanical deterioration.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.191-196
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• 1997

Steel is the most used as materials for construction and corrosion expansion of steel due to outdoor corrosive environmental factor bring serious problem on the durability of concrete structures time after time. It is the purpose of this study to see whether it is effective of not, when sacrificial anode method is adapted. Indoor accelerated corrosion testing was carried out to see its effective in a short term. From the mid result, potential of steel in concrete in case of adapting sacrifice anode method satisfacts protection standard value (less than-850mV vs CSE), therefore sacrificial anode method is considered as a proper protection steps against corrosion of steel.