• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.3
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• pp.51-58
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• 2008

Development of a new design guide which is based on empirical-mechanistic concept for pavement design is in action. It is called AASHTO 2002 Design Guide in USA and the KPRP(Korean Pavement Research Project) in Korea. The material characteristic of hot mix asphalt is a key role in the design guide. Therefore it is urgent to get a proper materials database, especially the dynamic modulus of hot mix asphalt. In this research, dynamic modulus test, which is based on aged asphalt binder, has been carried out and proposed the predicted equation of dynamic modulus. Nine different hot mix asphalt with three different asphalt binder have been used for the dynamic modulus test. Short-term aging, which is covers the time for the production of asphalt plant, transportation, lay-down, and compaction, can be simulated at $135^{\circ}C$ with 2 hour curing. Long-term aging has been carried out for a performance period of asphalt pavement. The dynamic modulus of asphalt pavement increases with aging time. As the nominal aggregate size increases, the change of dynamic modulus is not big.

• 한국도로학회:학술대회논문집
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• 2008.03a
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• pp.119-124
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• 2008

• 한국도로학회:학술대회논문집
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• 2008.10a
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• pp.279-286
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• 2008

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.4199-4204
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• 2011

The dynamic modulus of hot mix asphalt is one of the important indicators to evaluate the durability and performance of asphalt pavement. In resent, the dynamic modulus is suggested by a key property of asphalt pavement design and analysis in AASHTO 2002 Design Guide and Korean Pavement Research Project(KPRP). Master curve from laboratory test results should be needed for pavement design and analysis. The process to get the master curve is standardized. But, there are some setup and testing error at low temperature(-$10^{\circ}C$) and high temperature ($55^{\circ}C$). In this paper, a simplified process which is used 3 testing temperatures (5, 21, 40) is adopted to get the master curve. Comparison was carried out for standard process and simplified process. The suggested process can be used to get the master curve of asphalt pavement, even though some difference was shown at high temperature.

• International Journal of Highway Engineering
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• v.14 no.3
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• pp.15-24
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• 2012

The MEPDG(Mechanistic-Empirical Pavement Design Guide) developed based on the AASHTO Design Guide helps engineers find optimal alternatives by using traffic volume, climate, material property, and pavement structure as its input parameters. However, because technical problems were found in the MEPDG, efforts to improve the program by settling the problems have been continued. Meanwhile, another mechanistic-empirical design program has been developed by the KPRP(Korea Pavement Research Program) in Korea. To develop and improve the Korean design program reasonably, it is necessary to analyze the MEPDG and then compare programs each other. For concrete pavement, fatigue cracking is predicted by using very complicated logic different from other performance indicators. Therefore, in this paper, transfer functions of the fatigue cracking used in the version of 0.5, 1.0, and 1.1 of the MEPDG were analyzed. Sensitivity of the input parameters to the cumulative fatigue damage was compared to each other by the MEPDG version and KPRP.

• International Journal of Highway Engineering
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• v.7 no.4 s.26
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• pp.1-8
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• 2005

Permanent Deformation is one of the most important load-related pavement distresses in asphalt pavements. The Korean Pavement Design Guide currently being developed adopted the mechanistic-empirical approach and needed the pavement distress prediction models. This study intends to develop the model for prediction of permanent deformation in the asphalt layer and estimate the pavement performance. The objectives of this paper are to figure out the factors affecting the permanent deformation and then develop the permanent deformation prediction model for asphalt mixtures. The repeated triaxial load test was Performed on the 19mm dense graded asphalt mixture with variation of temperature and air void. Results from the laboratory tests showed that temperature and air void in asphalt mixtures have significantly influenced on the factors in prediction model. The permanent deformation prediction model for 19m dense grade asphalt mixtures has been developed using the multiple regression approach and validated the proposed permanent deformation prediction model.

• Journal of the Korean Society for Railway
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• v.17 no.2
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• pp.114-122
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• 2014

An asphalt trackbed is to be adapted in Korea to provide better bearing capacity and stability to the track and a comfortable ride to passengers. The dynamic modulus of Hot Mixed Asphalt(HMA) mixes is a critical design input parameter to determine the thickness of the asphalt trackbed. In this study, impact resonant tests and ultrasonic test methods are designed to obtain the dynamic modulus. These test methods are also verified to check the etffectiveness of constructing a master curve of the dynamic modulus over a wide range of frequencies and temperatures. The test results are compared to the computed dynamic modulus using AASHTO 2002 and the KPRP's proposed model. It can be concluded that the proposed simple test methods are effective to obtain the dynamic moduli of the asphalt mixes for the design of an asphalt trackbed foundation.

• International Journal of Highway Engineering
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• v.5 no.4 s.18
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• pp.1-11
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• 2003

Recently, the new pavement design method considering Korean environment and the specification for improving performance of pavement are being developed in Korea. The Jointed Concrete Pavement Program Applying Load Discretization Algorithm (called HEART-JCP) is one of the results of Korea Pavement Research Project in Korea. HEART-JCP program is developed to analyze various loading condition using the load discretization algorithm without mesh refinement. In addition, it can be modified easily into multi-purpose concrete pavement nidyses program because of the modularized structure characteristic of HEART-JCP. The program consists of basic program part and load discretization part. In basic program part, the displacement and stress are computed in the concrete slab, sub-layer, and dowel bar, which are modeled with plate/shell element, spring element and beam element. In load discretization program part, load discretization algorithm that was used for the continuum solid element is modified to analyze the model with plate and shell element. The program can analyze the distributed load, concentrated load, thermal load and body load using load discretization algorithm. From the result of verification and sensitivity study, it was known that the loading position, the magnitude of load, and the thickness of slab were the major factors of concrete pavement behavior as expected. Since the result of the model developed is similar to the results of Westergaard solution and ILLISLAB, the program can be used to estimate the behavior of jointed concrete pavement reasonably.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1999.11a
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• pp.75-78
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• 1999

근래 들어 농업생산기술분야에서 변량적 포장 작물관리를 의미하는 정밀농업이라는 단어가 자주 등장한다. 정밀농업은 80년대 초반 미국에서 시작된 농법으로 정밀농업(precision farming or precision agriculture), 처방농업(prescription farming), 국부 특성에 맞는 작물관리(site-specific farming/management), 변량형 농업(variable rate agriculture) 등의 다양한 명칭으로 불리운다. 정밀농업의 중심과제는 포장내의 변이(variation), 즉, 토양의 이ㆍ화학 특성과 작물의 생육ㆍ수량에 나타나는 포장내의 불균형을 어떻게 평가하고 이를 기준으로 하여 어떻게 포장ㆍ작물관리를 수행하는가 하는 점이다. (중략)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.487-493
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• 2017

The main purpose of this study is to evaluate the main parameters involved in the asphalt pavement distresses, including IRI (International Rough Index), fatigue, and permanent deformation. The main parameters are the region (Seoul and Busan), traffic level, asphalt binder, maximum aggregate of surface course, thickness of the surface course and base. A total of 64 case studies were carried out under the auspices of the KPRP (Korea Pavement Research Program). From the analysis of the KPRP test results, the key factors for the asphalt pavement distress were determined. Considering the effect of one variable in the basic condition, asphalt binder was the major factor having an effect on the distresses for an AADT (Annual Average Daily Traffic) of 5000 in the Seoul area. Among the remaining factors, the results were found to be in the order of the base layer thickness (A), surface layer thickness (B), and aggregate particle size thickness (D). The same results were obtained for an AADT of 10000. In the case of Busan with an AADT of 5000, the same result was obtained as for Seoul. Among the remaining factors, the results were in the order of the base layer thickness (A), aggregate particle thickness (D), and surface layer thickness (B). Even though there was a slight difference in the effect of the traffic level and region, asphalt binder was the parameter having the greatest effect on the asphalt pavement distress. In the case where the effect of multiple parameters was analyzed, the combination of the asphalt binder and base thickness showed a relatively strong effect.