• International Journal of Highway Engineering
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• v.16 no.4
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• pp.1-9
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• 2014

PURPOSES: The objective of this study is to evaluate construction issues and design for transverse steel in continuously reinforced concrete pavement(CRCP). METHODS : The first continuously reinforced concrete pavement(CRCP) design procedure appeared in the 1972 edition of the "AASHTO Interim Guide for Design of Pavement Structures", which was published in 1981 with Chapter 3 "Guide for the Design of Rigid Pavement" revised. A theory that was accepted at that time for the analysis of steel stress in concrete pavement, called subgrade drag theory(SGDT), was utilized for the design of reinforcement of CRCP - tie bar design and transverse steel design - in the aforementioned AASHTO Interim Guide. However SGDT has severe limitations due to simple assumptions made in the development of the theory. As a result, any design procedures for reinforcement utilizing SGDT may have intrinsic flaws and limitations. In this paper, CRCP design procedure for transverse steel was introduced and the limitations of assumptions for SGDT were evaluated based on various field testing. RESULTS: Various field tests were conducted to evaluate whether the assumptions of SGDT are reasonable or not. Test results show that 1) temperature variations exist along the concrete slab depth, 2) very little stress in transverse steel, and 3) warping and curling in concrete slab from the field test results. As a result, it is clearly revealed out that the assumptions of SGDT are not valid, and transverse steel and tie bar designs should be based on more reasonable theories. CONCLUSIONS : Since longitudinal joint is provided at 4.1-m spacing in Korea, as long as joint saw-cut is made in accordance with specification requirements, the probability of full-depth longitudinal cracking is extremely small. Hence, for transverse steel, the design should be based on the premise that its function is to keep the longitudinal steel at the correct locations. If longitudinal steel can be placed at the correct locations within tolerance limits, transverse steel is no longer needed.

• International Journal of Highway Engineering
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• v.16 no.6
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• pp.1-8
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• 2014

PURPOSES : Analysis and design of asphalt concrete (AC) and continuously reinforced concrete (CRC) composite pavements. METHODS : In this study, the service life of the AC/CRC composite pavements was determined based on the probabilistic method in the mechanistic-empirical pavement design guide(MEPDG). Typical pavement design was provided with respect to heavy truck traffic volume of highways. RESULTS : The service life of the composite pavements based on IRI was shorter than that based on rutting at lower traffic volume, but this trend was switched at higher traffic volume. CONCLUSIONS : It is concluded that the main distress affecting the service life of the composite pavements was longitudinal roughness and rutting. Roughness became lower, but rut depth became greater as the stiffness of the CRC increased.

• International Journal of Highway Engineering
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• v.19 no.5
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• pp.21-31
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• 2017

PURPOSES : One of the main components of road projects funded by the Economic Development Cooperation Fund (EDCF) is the improvement or rehabilitation of existing pavements. The result is that pavement structures are critical to the success of a project. There is, however, no design standard available at present that reflects a region's specific features including climate conditions and quality of pavement materials. For this reason, a comparative study of the major EDCF borrowers' flexible pavement design standards was conducted. This study led to the proposal of a new method for applying flexible pavement designs which can be used for EDCF-funded projects in Asia. METHODS : The method has been produced by adjusting some input data of the "AASHTO Interim Guide for Design of Pavement Structures" in accordance with certain Asian countries' geometrical features, tropical and subtropical weather, and strength of pavement materials. The Philippine regional factors, having five different grades, have been selected after taking into consideration the amount of rainfall, strength of pavement materials, and characteristics of the Asia and Pacific regions. Structural layer coefficients have been prepared for two different regions according to the geometric difference between Southeast and Southwest Asia. The Philippine and Sri Lankan coefficients have been used for Southeast Asia and Southwest Asia, respectively. CONCLUSIONS : Owing to applying this new method, it was verified that the thickness of the pavement was underestimated by between 11 cm and 16 cm compared with the originally designed thickness. Having discovered that the use of the Korean and American-oriented factors and coefficients is not appropriate for other Asian countries, the new method is expected to enhance the quality of pavement in future projects.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.6
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• pp.46-54
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• 2015

Base on Korean design code, previous design code had not considered the effect of pavement on the orthotropic steel deck, however recent design code (Limit State Design Method, 2012) allowed to consider the effect of pavement on the orthotropic steel deck, and efforts to apply the stiffness of pavement to the deck continue. Meanwhile, research on the effect of ultra thin bridge deck overlay on the orthotropic steel deck is inadequate, previous study was limited in about fatigue stress and performance between pavement layer and the orthotropic steel deck. In this study, according to changing of pavement layer stiffness application, pavement materials, pavement thickness and steel deck thickness, analysis of deflection. In addition to base on this result, consider effectiveness of ultra-thin pavement stiffness application on the orthotropic steel deck.

• Geomechanics and Engineering
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• v.32 no.1
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• pp.35-47
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• 2023

Deformability of road pavements in the form of ruts represent a safety risk for road users. In the procedures for dimensioning the pavement structure, the requirement that such deformations do not occur is imperatively included, which results in the appropriate selection of elements (material, geometry) of the pavement structure. Deformability and functionality, will depend of the correct design of pavement structure during exploitation period. Nevertheless, there are many examples where deformations are observed on the pavement structure, in the form of rutting at parts of the road with relatively short length, realised in the same climatic and the same geoenvironmental conditions. The performed analysis of deformability led to the conclusion that the level of deformation is a function of the speed of traffic. This effect is observed on city roads, but also outside of urban areas at roads with speed limits are significant, due to the traffic management, traffic jams (intersections, etc.). Still, the lower speed cause greater deformations. The authors tried to describe the deformability of flexible pavement structures, from the aspects of geotechnical problems, as a function of driving speed. Outcome of the analysis is a traffic load correction coefficient, in terms of using the existing methods of flexible pavement structures design.

• International Journal of Highway Engineering
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• v.4 no.1 s.11
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• pp.123-134
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• 2002

Special pavement test sections were selected to develop a distress prediction model on asphalt pavement of National Highway. Experimental design was conducted for the selection of LTPP sections on in-service pavement(new and overlaid pavement) using several variables affecting pavement performance. Preliminary sections that satisfied the design template were chosen from the national highway database, and final selection was fixed through field inspection. The number of monitoring section is 95 including 47 overlaid pavement. A pavement distress data such as crack and rutting were collected for two years. An interim pavement performance analysis was peformed to show feasibility of performance monitoring program. Data related pavement such as traffic, weather, material characteristic and crack etc. should be collected for next project years and distress prediction model will be developed through the statistical analysis.

• Journal of the Korean Geotechnical Society
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• v.33 no.12
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• pp.75-80
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• 2017

Permeable block pavement systems are widely used to relieve the flood and enhance water circulation. However, domestic design method has not yet been established well. Although AASHTO 93 flexible pavement design method is applied as a structural design method outside the country, there is a lack of information on layer coefficient of the permeable pavement materials, which makes it difficult to apply the design to various materials. Therefore, in this study, a method of calculating the layer coefficient of permeable block pavement materials by plate load test was presented and the layer coefficient of a permeable block pavement in a testbed was evaluated. Overall, calculated layer coefficient of open graded aggregate and permeable block pavement surface layer were similar to those of the conventional values. The presented method may be used to evaluate layer coefficients of permeable block pavements for design.

• Advances in Computational Design
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• v.7 no.4
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• pp.371-393
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• 2022

This paper presents a three-dimensional flexible pavement simulated in ANSYS subjected to moving vehicular load on the surface of the pavement typical for the road section in Nepal. The adopted finite element (FE) model of pavement is validated with the classical theoretical formulations for half-space pavement. The validated model is further utilized to understand the damping and dynamic response of the pavement. Transient analysis of the developed FE model is done to understand the time varying response of the pavement under a moving vehicle. The material properties of pavement considered in the analysis is taken from typical road section used in Nepal. The response quantities of pavement with nonlinear viscoelastic asphalt layer are found significantly higher compared to the elastic pavement counterpart. The structural responses of the pavement decrease with increase in the vehicle speed due to less contact time between the tires of the vehicle and the road pavement.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.5
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• pp.879-890
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• 2017

The US Pavement Design method (AASHTO) and HDM-4, a road pavement maintenance decision system, are not suitable for domestic pavement design, construction and maintenance. KPRP(Korea Pavement Research Program) has been developed to reflect Korea's environmental conditions and vehicle characteristics, thereby, extending pavement life. The main objective of this study is to select the best alternative through Life Cycle Cost $CO_2$ (LCCC) calculations among three representative maintenance strategies using KPRP design software since the environment cost resulting from the extended pavement life will also differ. The analysis of this study illustrates that cumulative carbon emissions for 40 years in alternative 2 (Cutting and Overlaying at Year 30) is the lowest option among them, and the basic cost of $CO_2$ emission by various road maintenance and repair work can be used for suggesting an optimal maintenance strategy for highway agency.

• International Journal of Highway Engineering
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• v.19 no.3
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• pp.1-10
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• 2017

PURPOSES : This paper focuses on strength development according to the mix design with cement type and mineral admixture from laboratory and field tests in cool weather. METHODS : Two methods evaluated the mix design of concrete pavement in cool weather. Firstly, laboratory tests including slump, air contents, setting time, strength, maturity, and freezing-thawing test were conducted. Three alternatives were selected based on the tests. Secondly, a field test was conducted and the optimum mix design in cool weather was suggested. RESULTS : It is an evident from the laboratory test that a mix with type III cement showed better performance than the one with type I cement. There was a delay in strength development of a mix with mineral admixture compared to mix design without any mineral admixture. In the field test, type III cement+flyash 20% mix design proved the best performance. CONCLUSIONS : For concrete pavement in cool weather, mix design using type III cement could overcome the strength delay due to mineral admixture. Moreover, it is possible to make sure of durability of pavement. Therefore, strength and durability problems due to cool weather would decrease.