• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.3 no.1
• /
• pp.43-51
• /
• 1983

The fatigue failure envelopes for the prediction of the fatigue life of asphalt pavements were obtained from the results of laboratory fatigue test for asphalt mixture. The envelopes did not depend on the experimental temperature and the number of loading, and varied with the types of asphalts. In the case of dense graded asphalt concrete, the envelopes formed a single curve regardless of the penetration of the asphalt. On the other hand, the method for the fatigue life prediction was presented based on the envelopes obtained and the triple layered elastic theory developed by Burmister.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.18 no.1_2
• /
• pp.33-38
• /
• 2012

Modified atmosphere packaging (MAP) was applied to steamed bread added with black rice in 10%. In terms of storage stability, the steamed bread was found to be susceptible to microbial spoilage and could be helped in its preservation and shelf life extension by MAP. According to microbial and sensory quality criteria, the product shelf life was determined as < 5 days for air package, 5 days for 100% $N_2$ package, 8 days for package of 60% $CO_2$/40% $N_2$, and 15 days for 100% $CO_2$ package. Even though MAP condition with $CO_2$ inclusion was effective in extending the shelf life based on microbial quality, it did not affect the staling of the bread.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.6D
• /
• pp.951-960
• /
• 2006

Structural pavement analysis considering lateral loads of moving vehicle was carried out in order to simulate passing vehicle loads under various interface conditions. To verify of existing multi-layer elastic analysis of layer interface effect parameters, this study compared outputs by using ABAQUS, a three dimensional finite element program and KENLAYER, multi-layer elastic analysis as vertical load was applied to the surface of asphalt pavements. Pavement performance depending on interface conditions was quantitatively evaluated and fundamental study of layer interface effect parameters was performed in this study. As results of the study, if only vertical loads of moving vehicle is applied, subdivision of either fully bonded or fully unbonded is enough to indicate interface effect parameters. On the other hand, when lateral loads are applied with vertical loads, pavement behavior and performance are greatly changed with respect to layer interface conditions. The thinner thickness of the asphalt layer is and the smaller elastic moduli of the asphalt layer is, the more pavement behavior is influenced by interface conditions. In addition, regression analysis equation analytically computing tensile strain which was considered thicknesses and elastic moduli of the asphalt layer and layer interface effect parameters at the bottom of the asphalt layer was presented using database from numerical analyses on national pavement model sections.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.17 no.2
• /
• pp.33-37
• /
• 2011

Real time control logic of microbial shelf life of a perishable food, seasoned pork meat has been formulated which exploits monitoring of $CO_2$ concentration of the package. The potential of the proposed logic was examined for storage at dynamic temperature conditions. The start of increase in $CO_2$ production rate from the food or rate of package $CO_2$ concentration change was found to coincide with the point of microbial quality limit and could be used as an index of microbial shelf life determination. This also corresponded to lag time of $CO_2$ concentration change or time for the $CO_2$ concentration to reach a certain value. The application potential of the proposed logic was confirmed for a sensor system to measure on real time and transmit the $CO_2$ concentration wireless to the computer system.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.32 no.4D
• /
• pp.345-356
• /
• 2012

Road pavement requires repetitive maintenance works to maintain satisfactory service level to the public. However, the repetitive maintenance works upon deteriorated pavement structure make negative effects to deterioration speed. It often leads to inefficient use of limited budget. For that reason, the pavements require reconstruction work to recover their original performance. Recently, construction demands in the Korean national highway have already been reached to maximum level, and the aged pavements start to demand much more reconstruction works. However, in the real world, road agencies have often been confused when they determine maintenance design for such aged road sections due to budget constraint. It is because there is no reliable long-term maintenance strategy that supports their decision making. To support their decision making, this paper aimed to suggest the best maintenance strategy considering changing process of pavement performance by repetitive maintenance works. As an analysis method, probability distribution and hazard function to estimate the life expectancy were adopted, and then the results were used for long-term life cycle cost analysis with deterministic or Monte-Carlo method under various scenarios. As an empirical study, the Korean national highway data that has long-maintenance history data since 1986 has been applied. Last, this paper considered quality assurance of maintenance work to improve maintenance quality. These could be important information as a part of long-term maintenance strategy of pavement.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.33 no.4
• /
• pp.1651-1664
• /
• 2013

Precise analysis on deterioration processes of road pavements is not so simple matter due to severe uncertainty originated from a lot of explanatory variables engaged in. For those reasons, most analytical models for pavement deterioration prediction have often preferred to probabilistic approaches than deterministic models. However, the general probabilistic approaches that treat overall characteristics of population or entire sample would not be suitable for providing detail or localized information on their changing process. Considering the aspects, this paper aimed to suggest a stochastic disaggregation method to analyze the localized deterioration speeds and its variances changed by time and condition states. In addition, life expectancies and their uncertainty were estimated by probabilistic algorithm using the disaggregated stochastic process. For an empirical study, pavement inspection data (crack) accumulated from 2003 to 2010 from Korean national highway network was applied. This study can contribute to securing reliability of life cycle cost analysis, which is one of the primary analyses in road asset management, with much advanced deterioration forecasting functions. In addition, it would be meaningful trials as fundamental research for preventive maintenance strategy that demands essential understanding on changing process of the deterioration speed of pavement.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.37 no.1
• /
• pp.133-141
• /
• 2017

Traffic volume increases according to highway expansion and industrial development which causes repetitive defect and durability degradation on pavement. The research of quality assurance system used abroad has introduced Korea. Korea Expressway Corporation (KEC) has developed a Quality Performance Index (QPI) that quantitatively assesses the level of quality of the final product, and practical applications. Assessment factor on concrete pavement consisted of pavement thickness, compressive strength, IRI and spacing factor. Assessment factor on concrete pavement is determined by empirical evaluation factor from abroad. In this study, analysis of evaluation factors of concrete pavement by using pavement life prediction simulation and measured data were evaluated with consideration of feasibility of the assessment factor. Pavement life, performance and durability are affected by pavement thickness, compressive strength, IRI and spacing factor in assessment factor on concrete pavement, QPI.

• International Journal of Highway Engineering
• /
• v.1 no.1
• /
• pp.97-106
• /
• 1999

This study was conducted to develop a test system for evaluating resistance against reflection cracking in shear mode caused by wheel load in asphalt concrete overlaid on the deteriorated cement concrete pavement. Reflection cracking resistance of selected polymer modified asphalt(PMA) mixtures with and without reinforcement was evaluated using this test system. It was shown that the test results accounted for the effectiveness of materials and reinforcement characteristics in terms of the difference in the resistance against reflection cracking. A shear failure life of a certain mixture was estimated with a high coefficient of determination. when the test results were used in a well known prediction model. Therefore, it seemed to be possible to use this technique for predicting a relative service life of on overlay.

• Agrochemical news magazine
• /
• v.16 no.1 s.124
• /
• pp.50-52
• /
• 1995

• 한국도로학회지:도로
• /
• v.3 no.1 s.7
• /
• pp.61-71
• /
• 2001