• International Journal of Highway Engineering
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• v.13 no.4
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• pp.61-70
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• 2011

This study developed a permanent deformation model for asphalt concrete based on shear properties. Repeated load triaxial compression (RLTC), triaxial compressive strength, and indirect tension strength tests were performed for the three types of asphalt mixtures at various loading and temperature conditions to correlate shear properties of asphalt mixtures to rutting performance. For the given mixtures, as testing temperature increased, cohesion decreased, but friction angle was insensitive to temperature at $40^{\circ}C$ or higher. It was observed that deviatoric stress, confining pressure, temperature, and load frequency affected the permanent deformation of asphalt mixtures significantly. The permanent deformation model based on shear stress to strength ratio and loading time was developed using the laboratory test results and calibrated using accelerated pavement test data. The proposed model was able to predict the permanent deformation of the asphalt mixtures in a wide range of loading and temperature conditions with constant model coefficients.

• Journal of the Korean Society for Railway
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• v.17 no.2
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• pp.123-132
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• 2014

In this study, permanent deformation of asphalt trackbed was investigated by performing repetitive load test on specimen made with dense graded asphalt mixture that was specially prepared for asphalt trackbed foundation. The obtained test results were compared with those computed from the prediction model proposed by AASHTO 2002, called MEPDG. No prediction model adaptable only for permanent deformation of the asphalt trackbed foundation has yet been developed, so the prediction model by AASHTO was adapted in this study to simulate permanent deformation of trackbed foundations in asphalt slab track and in ballasted asphalt track. In order to simulate permanent deformation, a finite element analysis was performed to obtain stresses generated in trackbed due to wheel load. It was found that the predicted permanent deformation was much smaller than the anticipated deformation and that the asphalt track could be stable during the service life of the structure.