• International Journal of Highway Engineering
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• v.4 no.3 s.13
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• pp.1-13
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• 2002

Design methods for new flexible pavements and overlays are in the transition from empirical to mechanistic approach, and many state highway agencies trend to move toward the adoption and use of mechanistic-empirical (M-E) design in new constructions and rehabilitations of flexible pavements. Hence, the Michigan Department of Transportation (MDOT) decided to develop a M-E flexible pavement design procedure, in which major pavement distresses such as fatigue cracking and rutting are employed as indicators of the serviceability of a flexible pavement. The main concept of the developed design procedure is that a designed pavement that is supposed to carry a certain number of traffic must satisfy designated thresholds of rut depths and fatigue lives during a service period. For the M-E design procedure, transfer functions were developed to predict rut-depths and fatigue lives. These functions related the pavement responses to pavement performance. For validation, three current new flexible pavement design cases were obtained from the MDOT. In these cases, asphalt concrete (AC) layer thicknesses determined by the suggested M-E procedure compare favorably with those determined by the current MDOT design practice that is based on AASHTO design guide. This finding implies that the suggested Michigan M-E flexible pavement design procedure can provide a good opportunity to improve the current design practice.

• 한국도로학회지:도로
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• v.3 no.4 s.10
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• pp.52-53
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• 2001

• International Journal of Highway Engineering
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• v.10 no.4
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• pp.79-89
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• 2008

The pavement performance model is the most important factor to determine the pavement life in the mechanistic-empirical pavement design guide (MEPDG). As part of Korean Pavement Research Program (KPRP), the Korean Pavement Design Guide (KPDG) is currently being developed based on mechanistic-empirical principle. In this paper, the rutting prediction model of asphalt mixtures, one of the pavement performance model, has been developed using triaxial repeated loading testing data. This test was conducted on various types of asphalt mixtures for investigating the rutting characteristics by varying with the temperature and air void. The calibration process was made for the coefficients of rutting prediction model using the accelerated pavement testing data. The accuracy of prediction model can be increased when by considering the effect of individual rutting properties of materials rather than shear stresses with depths.

• 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.

• 한국도로학회:학술대회논문집
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• 2002.10a
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• pp.301-308
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• 2002

• International Journal of Highway Engineering
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• v.5 no.1 s.15
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• pp.1-10
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• 2003

The objective of pavement design, just as with the design of other structures, is to obtain the most economical designs at specified levels of reliability. Methods that yield designs with different levels of reliability are undesirable, and over the course of time design approaches in the U.S. and Europe have converged toward the Load and Resistance Factor Design (LRFD) format in order to assure uniform reliability. At present the LRFD format has been implemented in concrete, steel, wood and bridge design specifications. In this paper, reliability theories are used to illustrate the development of an LRFD format for Mechanistic-Empirical (M-E) design of flexible pavements as an alternative of its reliability module. It is shown in this paper that ten candidate pavement sections designed with a reliability level using the AASHTO design guide (1986) do not have uniform structural reliability in terms of pavement mechanistic distress such as fatigue cracking and the uniform reliability can be achieved by using the LRFD format.

• International Journal of Highway Engineering
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• v.13 no.1
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• pp.33-40
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• 2011

The resilient modulus which is presented mechanical properties of compacted subbase material is the design parameter on the Mechanistic - Empirical pavement design guide. The compaction control method on the Mechanistic - Empirical pavement design guide will be the way to confirm whether the in-situ elastic modulus measured after the compaction meets the resilient modulus which is applied the design. The resilient modulus in this study is calculated by the neural network suggested by Korea Pavement Research Program, and degree of compaction as the existing compaction control test and plate bearing capacity test(PBT) was performed to confirm whether the in-situ elastic modulus is measured. The Light Falling Weight Deflectometer(LFWD) is additionally tested for correlation analysis between each in-situ elastic modulus and resilient modulus, and is proposed correlation equation and test interval which can reduced overall testing cost. Also, the subbase compaction control procedure based on the in-situ elastic modulus is proposed using the in-situ PBT and LFWD test result.

• International Journal of Highway Engineering
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• v.9 no.3
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• pp.101-110
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• 2007

Joint Spacing of Jointed Concrete Pavement has been uniformly designed and constructed as six-meter in Korea. However, engineering backgrounds to show the appropriateness of six-meter Joint Spacing has not been provided. In the on-going reseach of the development of Korea Pavement Reseach Program(KPRP), the optimum Joint Spacing is suggested as 6 to 8 meters according to the regional climatic conditions based on the mechanical-empirical analysis of short-term and long-term pavement distress. This study is a part of the investigation on the adequateness of Joint Spacing design specification suggested in KPRP. Joint Spacing was design and constructed as seven-meter Joint Spacing suggested as design specification in Korea Reseach Program(KPRP) and monitored the Load Transfer Efficiency(LTE), Random crack and compared with those of adjacent $6{\sim}7$ meter Joint Spacing concrete section.

• International Journal of Highway Engineering
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• v.10 no.3
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• pp.11-18
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• 2008

In recent, lots of researches for mechanical-empirical design concept for asphalt pavement are on going. AASHTO 2002 Design Guide in USA and KPRP(Korean Pavement Research Program) in Korea are under developing. In these programs, the mechanical properties of hot mix asphalt are a key role for design and analysis. Unfortunately, there is no proper database on the mechanical properties of hot mix asphalt, such as dynamic modulus. The use of dynamic modulus has couple of good advantages which is based on temperature, traffic loading and frequency on pavement. In this research, the verification of the relationship between maximum nominal aggregate size and dynamic modulus has been carried out. Also, test specimen size effect on dynamic modulus has been conducted. Considering the limitation of laboratory testing machine in Korea, test specimen with 100mm diameter and 150mm height is recommended for dynamic modulus test. Also, as the maximum nominal aggregate size increases, the dynamic modulus of hot mix asphalt increases.

• 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.