• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.771-781
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• 2006

This Study is about the development of LCC Analysis Model and Evaluation of VE. It was carried out to help the person's intention decision about choosing the pavement construction method that can deal with 'Pavement Life Factor' like Area Character and Traffic Volume efficiently, by considering the total life cycle cost of pavement life cycle happens according to the numbers of public use year. For this, we developed the new LCC Analysis Model by using the Data of Seoul city the representative city in Korea, and carried out VE Evaluation that reflects the opinions of specialists. This Analysis Model consists of cost items that affects directly the choice of pavement construction, except for the common cost items of the various pavement construction. And we investigated the propriety by applying our model to the example line that are used for the public at present. About the base data of cost items that are used for our analysis, we enhanced our model's confidence by using the statistics data of Seoul and the standard data of unit cost calculation.

• The Journal of the Korea Contents Association
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• v.11 no.12
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• pp.919-930
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• 2011

National highway is one of the social infrastructures that continue to be managed in order to serve their full functions. The national highway has been managed by the Pavement Management System (PMS) until now. The PMS manages the highway as a way of facility maintenance and maximizes the service life of the highway with minimum cost. The cost is evaluated mainly with a facility manager's perspective based on engineering judgment. People's needs of quality of life have been increased as their income level is rising and naturally the opinion of citizen as a taxpayer plays an important role in determining national policy. Therefore, the contentment of a user's perspective was the starting point of addressing these needs. The Level of Service began to be used as a measure for the evaluation of the user's perspective. In this thesis we would like to design an application and a data architecture for a pavement asset management system and to show how it meets the requirements of KTAM-40 Systems.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6D
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• pp.819-829
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• 2008

Fatigue cracking occurs over long time period because dynamic strength of slab continuously decreases by vehicle loading repetitively applied to the concrete pavement. To more accurately predict the fatigue life of the concrete pavement, the stress due to environmental loading should be considered prior to calculating the stress due to the vehicle loading because the stress due to temperature and moisture distribution always exists within the slab. Accordingly, a new fatigue model considering the environmental loading was developed in this research by evaluating factors of existing fatigue models most widely used and by making data points from the models. The applicability of the new model was evaluated by performing a fatigue analysis on the general concrete pavement structure using local climatic and traffic conditions in Korea. It was concluded that the top-down cracking due to the tensile stress at top of the slab is dominant cause of the fatigue failure than the bottom-up cracking occurred at bottom of the slab. More advanced fatigue analysis considering vehicle speed is expected by developing this study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.73-79
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• 2006

A major purpose of this study is to develop high modulus asphalt mixtures for perpetual asphalt pavements which can save maintenance cost by increasing the design and performance periods of the pavements. Various physical and mechanical laboratory tests are performed for the high modulus asphalt binder developed in this study. The test results show that the properties of the high modulus binder are similar to those of the French high modulus binders. In addition to the binder tests, various performance tests are conducted for the high modulus and conventional mixtures. The dynamic modulus test results indicate that the dynamic modulus values of the high modulus mixtures are higher than those of the conventional mixtures by 10~15% at $5^{\circ}C$, 20~25% at $15^{\circ}C$ and 100% at $30^{\circ}C$. It is observed from the performance tests that the high modulus mixtures yield better fatigue, rutting and moisture damage performance than the conventional mixtures.

• Food Science and Preservation
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• v.31 no.3
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• pp.433-443
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• 2024

This study investigated the effect of packaging method and root trimming on quality of green onions during storage. Two packaging methods (tied with string, S or packaged with film bag, FP) and two root trimming states (attaching the roots without trimming, AR or cutting the roots leaving about 5 mm, CR) were treated after harvest. Then, the green onions stored at 20℃ for 8 days and 1℃ for 6 weeks to investigate changes in quality. When stored at 20℃, the differences in marketability between S and FP were minimal, while when stored at 1℃, the marketability of the FP remained higher than that of S. The leaf color change in CR progressed faster than in the AR treatment group, leading to faster quality deterioration. The occurrence of weight loss, browning, and softening of stems progressed as the storage period elapsed. However, except weight loss, they were at a level that did not affect marketability within the marketability limit period determined by color change and wiltig of leaves. The allicin and quercetin contents of stems increased in the early stages when quality deteriorated after harvest but decreased as quality deterioration became more severe.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.21 no.2
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• pp.55-60
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• 2015

Packaging of export cut lilies reduces physical damage during distribution like dropping, shock, vibration, compression and serves to protect from necrosis, microbial contamination and decomposition. Study on which packaging materials must be selected is necessary because it serves to direct effect maintaining quality and the degree of freshness. newspaper, perforated OPP film, Oriented Nylon film (ON), punched OPP film, OPP films are used in this study. Plant senescence of lilies was happened rapidly during storage at $25^{\circ}C$ rather than at $5^{\circ}C$. Also, water absorption, fresh weight at during storage $25^{\circ}C$ rather than at $5^{\circ}C$ In addition, fresh weight of lilies storage at $25^{\circ}C$ appears higher than at $5^{\circ}C$ all of the packaging materials except OPP because water absorption of lily storage at $5^{\circ}C$ appears higher than at $25^{\circ}C$, thereby suppressing the fresh weight reducing Also, effect on biological activity of lilies from shape of packaging material appears higher during storage at $5^{\circ}C$ than at $25^{\circ}C$. Compared with each packaging materials, newspaper packaging is the smallest effect on changes in biological activity of cut lilies during storage. Thus, the results demonstrate that flowering date are affected mainly by the storage temperature rather than packaging materials.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.1
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• pp.21-25
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• 2009

The results of a recent case study for material characterizations and structural evaluation to design asphalt overlay thickness of William P Hobby airport in Houston, Texas are presented herein. The existing runway 12R-30L of Hobby airport consisted of thick asphalt overlay over Portland Cement Concrete (PCC) and the localized surface shoving as evident in the closure of surface groove has been observed recently. Using the field cored asphalt concrete mixtures, measurements of percent air voids, asphalt content and aggregate gradation were conducted to find out the causations of surface shoving and groove closure. The FAA layered elastic program, LEDFAA was utilized to evaluate pavement structural conditions for new asphalt overlay. Two different composition assumptions for existing pavement were made to evaluate the pavement as followings: 1) APC, Asphalt Concrete Overlay over PCC pavement and 2) AC, Asphalt Concrete pavement. Based on laboratory testing results, a ratio of percent passing #200 to asphalt content ranged 1.1 to 2.2, which is considered a high ratio and a tendency of tender mix design was observed. Thus, the localized surface shoving and groove closure of the runway 12R-30L could be attributed to the use of excessive fine contents and tender mix design. Based on the structural evaluation results, it was ascertained that the analysis assuming the pavement structure as AC pavement gives more realistic structural life when the asphalt overlay is thicker enough compared to PCC layer because the existing PCC pavement under asphalt overlay acts more like a high quality base material.

• International Journal of Highway Engineering
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• v.6 no.4 s.22
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• pp.91-100
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• 2004

This study was Performed to evaluate applicability of color flexible pavement concrete (CFPC) for motorway pavement. Color flexible pavement has been applied to non-motorway pavements, such as pedestrian and bicycle road. Two polymers were used to modify the binder and to strengthen the stiffness of pavement mixture. Waste paper was used to prevent the asphalt of gap-grade mixture from draining. Marshall properties, indirect tensile strength(ITS), tensile strength ratio(TSR) before and after freezing-and-thawing treatment and artificial aging, permanent deformation and fatigue life were measured. Color bituminous concrete mixtures used this study had nearly the same quality in mechanical properties when compared with conventional asphalt concrete mixtures manufactured with AP-3 and all mixtures satisfied with domestic specification for motorway pavement. Therefore, it is proved that the color bituminous concrete used this study can be applied for motorway pavement.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.19 no.2
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• pp.67-73
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• 2013

This study investigated the quality changes of Samgyetang during storage, resulting from various degassing methods used at the packaging stage. Three different samples were prepared, one without any treatment (CON), a second with reduced head space volume by squeezing the pouch (RHS), and a third by flushing with nitrogen gas (NGF). These were retorted at $120^{\circ}C$ for 65 min under the F-value of approx. 8.0, and stored at $25^{\circ}C$ for 9 months. The oxygen ratio in the head space and the dissolved oxygen content of NGF samples tended to be lower than those of other samples over the storage period. Compared to the CON, the acid values of NGF and RHS samples were lower than the CON from month 3 and 6 (p<0.05). During storage, volatile basic nitrogen values of NGF and RHS samples increased slowly compared to the CON. To delay quality deterioration and extend the shelf-life of Samgyetang products, the reduction of oxygen content in the head space of the retort pouch (preferably by flushing with nitrogen gas) is recommended, even though no significant differences in sensory evaluation were observed among the samples during 9 months of storage (p>0.05).

• International Journal of Highway Engineering
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• v.9 no.3
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• pp.111-121
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• 2007

During the whole month of December in 2005, Korea experienced both heavy snowfall and freezing temperature in southeast regions, which had caused frost related damages to many pavements laid on top of box culverts. In-situ observation revealed that the formation of ice lenses in subgrade and subsequent unbound layers led to upward heaving and transverse cracks in concrete and asphalt pavements. This has affected the long-term performance of pavements, as well as has threatened drivers' safety for a while. Recently, Korea Expressway Corporation has proposed a design guide to better protect newly constructed unbound pavement layers over culverts from frost heave. A trench drainage system has been selected to effectively draw off water and to alleviate pore-water pressure in soils during the coldest season. This paper presents experimental and analytical backgrounds behind this new design guide. Soil specimens retrieved from the sites are tested to quantify clay content and to estimate the permeability of subgrade. A 2-D ground seepage analysis has been conducted to better understand the changes in pore water pressures as a function of grain size. Finally, an optimum size of trench drainage is determined based on numerical analysis and workability in the field.