• International Journal of Highway Engineering
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• v.15 no.1
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• pp.47-56
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• 2013

PURPOSES: This study is to evaluate a ground water level effect on frost heaving in road pavements. METHODS: The effects of water table on frost heaving in pavement systems were evaluated from the mechanical analysis using FROST program. The input parameters and boundary conditions were determined by considering climates, pavement sections, and material properties specially subgrade soil types in Korea. RESULTS: When the water table located above the freezing depth, amount of frost heaving caused by freezing the water in pavement itself was big enough to damage in pavement system, although pavement system consists of fully non-frost-susceptible materials with sufficient thickness of anti-freezing layer. The amount of frost heaving was decreased rapidly with increasing the distance between the water table and freezing depth. CONCLUSIONS: It was concluded that there is no engineering problems related with frost heaving in practical sense when the distance between freezing depth and water table is over 1.5m for having subgrade soils less than 50% of #200 sieve passing to meet specification on quality control in Korea.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.205-216
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• 2009

As a subsequent study, this paper presents a comparative evaluation of structural responses in asphalt pavements with stabilized foundations. The approach based on a finite element analysis which incorporates non-linear behaviors of pavement geomaterials is used to estimate each performance indicator under standard single axle loading condition. In addition, results from laboratory tests are used to provide physical and mechanical properties of stabilized geomaterials for analyzing various pavement structures. Changes in pavement responses with varying layer thickness and stabilizer contents were investigated. It is found that the effect of layer thickness and stabilizer content is a critical factor in structural response of stabilized pavements. Moreover, a design criterion is proposed for selecting minimum contents of stabilizer of coarse-grained geomaterials based on a result of unconfined compressive strength and proper layer thickness of foundations.

• Water Engineering Research
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• v.5 no.1
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• pp.37-45
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• 2004

As one alternative to alleviate damages caused by stormwater runoff, the effects of runoff quantity reduction are analyzed when porous pavement is used. Porous pavements with various depths, general pavement and an artificial rainfall generator are installed for laboratory experiments. Runoff changes are analyzed according to the various rainfall durations. The rainfall intensity of 150 mm/hr is generated for 30 minutes, 60 minutes, and 120 minutes. For porous pavements with 80 cm thickness, 100%, 93%, 56% of discharge is infiltrated through soil, respectively. For porous pavements with 20 cm thickness, 81%, 32%, 28% of discharge is infiltrated through soil, respectively. It is found that the porous pavements are able to decrease the runoff.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.337-340
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• 2008

The important factors that should be considered when designing and constructing the precast prestressed concrete pavement were investigated in this study. Those factors included traffic and environmental loads, interaction between the concrete slab and the underlying layers, determination of the slab thickness and the prestressing amount. In addition, the behaviors of the precast prestressed concrete pavement when post-tensioning was applied were analyzed using a finite element model. The effects of the number of anchors, the horizontal resistance of underlying layers, the pavement length, the slab thickness, and the bearing area of the anchorage on the distribution of compressive stresses were analyzed.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1091-1094
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• 2000

An experimental study is carried out to estimate the way of applying the granulated blast furnace slag[GBFS] to the lean concrete subbase of concrete pavement. According to the test results, this application seems promising. For this application, mixing percent of GBFS ranging from 30 to 45 is recommendable at this stage. Expected benefits using GGBFS in the field of concrete pavement include reduced shrinkage crack, reduced pavement thickness, and extended service life.

• International Journal of Highway Engineering
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• v.18 no.1
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• pp.85-90
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• 2016

PURPOSES : The objective of this paper is to understand the deterioration phenomenon and causes in the pavement of a ramp area. METHODS : Ramp areas need to be sloped because of the centrifugal force, which depends on the vehicle speed and grade of the ramp area. As a result, vertical and horizontal forces are applied on the pavement surface of the ramp area. Furthermore, the horizontal force depends on the vehicle speed and grade of the ramp area. In order to analyze the pavement structure of a ramp area, a multi-layered elastic analysis program was used to evaluate the weakest link of fatigue cracking deterioration, according to the simultaneously applied vertical and horizontal forces. RESULTS : From case studies related to the bonding conditions between the surface and base layer in a ramp area, it was found that the partially bonded cases resulted in a critical potential of fatigue cracking deterioration, in a comparison of 50%, 70%, and fully bonded cases. CONCLUSIONS : According to the results of the case studies, the pavement structure system should be reinforced by upgrading the material or increasing the thickness compared to the general pavement areas, in order to provide a performance life similar to the mainline pavements in the ramp areas.

• International Journal of Highway Engineering
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• v.18 no.2
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• pp.19-27
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• 2016

PURPOSES: The behavior of a concrete pavement in a tunnel was investigated, based on temperature data obtained from the field and FEM analysis. METHODS: The concrete pavement in a tunnel was evaluated via two methods. First, temperature data was collected in air and inside the concrete pavement both outside and inside the tunnel. Second, FEM analysis was used to evaluate the stress condition associated with the slab thickness, joint spacing, dowel, and rock foundation, based on temperature data from the field. RESULTS : Temperature monitoring revealed that the temperature change in the tunnel was lower and more stable than that outside the tunnel. Furthermore, the temperature difference between the top and bottom of the slab was lower inside the tunnel than outside. FEM analysis showed that, in many cases, the stress in the concrete pavement in the tunnel was lower than that outside the tunnel. CONCLUSIONS : Temperature monitoring and the behavior of the concrete pavement in the tunnel revealed that, from an environmental point of view, the condition in the tunnel is advantageous to that outside the tunnel. The behavior in the tunnel was significantly less extreme, and therefore the concrete pavement in the tunnel could be designed more economically, than that outside the tunnel.

• International Journal of Highway Engineering
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• v.17 no.1
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• pp.69-75
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• 2015

PURPOSES : The objective of this study is to evaluate the effectiveness of a geogrid reinforced subbase of permeable flexible pavement structures with respect to permanent deformation. METHODS : Experimental trials employing a repeated triaxial load test scheme were conducted for both a geogrid reinforced subbase material and a control specimen to obtain the permanent deformation properties based on the VESYS model. Along with this, a finite element-based numerical analysis was conducted to predict pavement performance with respect to the rutting model incorporated into the analysis. RESULTSAND CONCLUSIONS : The results of the experimental study reveal that the geogrid reinforcement seems to be effective in mitigating permanent deformation of the subbase material. The permanent deformation was mostly achieved in the early stages of loading and then rapidly reached equilibrium as the number of load applications increased. The ultimate permanent deformation due to the geogrid reinforcement was about 1.5 times less than that of the control specimen. Numerical analysis showed that the permeable, flexible pavement structure with the geogrid reinforced subbase also exhibits less development of rutting throughout the service life. This reduction in rutting led to a 20% decrease in thickness of the subbase layer, which might be beneficial to reduce construction costs unless the structural adequacy is not ensured. In the near future, further verification must be conducted, both experimentally and numerically, to support these findings.

• Geomechanics and Engineering
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• v.12 no.2
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• pp.257-267
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• 2017

This paper presents laboratory investigation of stabilization of subgrade soil. One type of soil and three types of stabilizers i.e., hydrated lime, class F fly ash and polypropylene fibres are selected in the study. Atterberg limit, compaction, california bearing ratio (CBR), unconfined compressive strength and triaxial shear strength tests are conducted on unstabilized and stabilized soil for varying percentage of stabilizers to analyze the effect of stabilizers on the properties of soil. Vertical compressive strains at the top of unstabilized and stabilized subgrade soil were found out by elasto-plastic finite element analysis using commercial software ANSYS. Strategy for design of optimum pavement section was based on extension in service life (TBR) and reduction in layer thickness (LTR). Extension in service life of stabilized subgrade soil is 6.49, 4.37 and 3.26 times more due to lime, fly ash and fibre stabilization respectively. For a given service life of the pavement, there is considerable reduction in layer thicknesses due to stabilization. It helps in reduction in construction cost of pavement and saving in natural resources as well.

• International Journal of Highway Engineering
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• v.5 no.4 s.18
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• pp.13-22
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• 2003

Several design methods from overseas are employed without considering different conditions such as material properties, climate, and traffic condition in this country. Therefore, there are limitations in application. Therefore, new pavement analysis system which is able to design a pavement efficiently and economically should be set up. In this study, 243 probable sections are classified depending on values of layer thickness and elastic modulus, and the effect of load types for the probable sections are analyzed. The section showing larger load distribution is chosen for analysis. As a result of sensitivity, a layer thickness has more influence on pavement than an elastic modulus does. The stress distribution of FWD test load is larger than that of circular load. This study compares outputs between nonlinear elastic model and linear elastic model. Based on the result, this study finds nonlinear elastic model considering stress condition in the ground is recommended for subbase.