• International Journal of Highway Engineering
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• v.4 no.1 s.11
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• pp.161-170
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• 2002

This study is a fundamental research for recycling waste polyethylene film(WPF) in asphalt concrete for roadway pavement. The objective of this study is to develop technology of making waste polyethylene asphalt mixture and evaluate properties of the asphalt concrete containing WPF. Asphalt concrete for surface course of pavement was produced through an appropriate mix-design using dense-graded and gap-graded aggregates. Marshall mix design, indirect tensile strength test, wheel tracking test and tensile fatigue test were performed. Test result showed that some WPF asphalt mixtures had a high tensile property and good resistances against rutting and fatigue cracking, compared with normal asphalt mixture.

• International Journal of Highway Engineering
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• v.15 no.4
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• pp.117-125
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• 2013

PURPOSES : The purpose of this study is to evaluate of field application and laboratory performance of warm-mix asphalt (WMA) according to the dosage rate of organic-based WMA additive. METHODS: Three asphalt mixtures, i.e., hot mix asphalt (HMA), WMA with the dosage rate of 1.5%, WMA with the dosage rate of 1.0%, were sampled from the asphalt plant when the field trial project were constructed. With these mixtures, the laboratory testings were performed to evaluate the linear viscoelastic characteristics and the resistance to moisture, rutting and fatigue damage. RESULTS : From the laboratory test results, it was found that the WMA with the reduced dosage rate of additive would be comparable to HMA and WMA with the original dosage rate in terms of the dynamic modulus, tensile strength ratio, rutting resistance. However, the fatigue reisistance of WMA with the reduced dosage rate was slightly worse but it should be noted that the fatigue performance is necessarily predicted by combining the material properties and pavement structure. CONCLUSIONS: Through the field construction and laboratory testings, the dosage rate of organic-based WMA additive could be reduced from 1.5% to 1.0% without the significant decrease of compactability and laboratory performance. The long-term performance of the constructed pavement will be periodically monitored to support the findings from this study.

• International Journal of Highway Engineering
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• v.15 no.1
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• pp.75-86
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• 2013

PURPOSES: The purpose of asphalt pavement reducing surface temperature by using Pipe cooling system is to make pleasant city life environment. METHODS: We considered building condition to lay the pipes under asphalt pavement and figured out that temperature reducing effect with pipe cooling system. In addition, we guessed rutting through wheel tracking test with a laid the pipes under asphalt mixture and performed fatigue cracking through a flexural fatigue test for performance evaluation of pipe cooling system. RESULTS: When pipe cooling system worked, the temperature of pavement model reduced quickly in test. The system can turn down the degree by 4 or 5 quickly as well. It didn't affect rutting to lay the pipes under the pavement, but it can get damaged to asphalt pavement in early stage by the result of performance evaluation. CONCLUSIONS: We figured out that pipe cooling system can turn down the temperature of aspalt pavement surface through tests. We suggest that pipe cooling system should be considered one of the effective way to solve urban heat island problem.

• Journal of the Korean Geotechnical Society
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• v.23 no.3
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• pp.15-24
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• 2007

This paper will present a simple approach (or predicting layer deformation of unbound pavement materials with stress-dependent material properties. The approach is based on an uncoupled formulation in which the resilient and deformation response of unbound materials are considered separately. As a result, an uncoupled approach incorporating a resilient stiffness and Poisson's ratio model is able to simulate field measured deformation in pavement foundations. In addition, a sensitivity analysis is conducted to identify the significant factors in the stress-dependent modulus and Poison's ratio model. The predicted trends of deformation from this analysis are presented and discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5D
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• pp.619-625
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• 2009

Test constructions were performed at 3 sites to investigate ways for maximizing performance of geogrid-reinforced asphalt pavements known to reduce reflection cracking and rutting. Problems during construction operation which can affect bonding shear strength of the geogrid-reinforced asphalt pavements were defined and the construction conditions were intentionally made during the test constructions. Both immediately and 1year after the test constructions, cores were obtained from positions with good and bad construction conditions and then bonding shear strength tests were performed to be compared each other. Rules to be kept at construction sites were suggested to improve performance of the geogrid-reinforced asphalt pavements.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1D
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• pp.53-60
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• 2010

The objective of this paper is to evaluate a performance-based load zoning procedure in flexible pavements. Long-term performance in flexible pavements will be evaluated using VESYS type rutting model and Miner s theory on fatigue cracking. Permanent deformation properties such as alpha and gnu, and fatigue cracking properties such as k1 and k2 in asphalt concrete were used respectively. The data from the literatures were also used in predicting performance in flexible pavements for evaluating load restrictions as well as parametric study. Finally, a performance-based load zoning procedure and a simple load limit procedure for load zoning were assessed.

• International Journal of Highway Engineering
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• v.12 no.2
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• pp.17-23
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• 2010

Since the relatively stiff binder shows a higher tensile strength as well as higher rutting resistance, it is believed that the binder stiffness is an important factor for rutting and tensile strength of asphalt mixtures. The typical tensile property is measured by indirect tensile strength (ITS) test at $25^{\circ}C$ and the rutting resistance is most widely measured by wheel tracking (WT) test at $60^{\circ}C$. The deformation strength ($S_D$) is newly developed property to estimate rut resistance of asphalt concretes at $60^{\circ}C$. The ITS and $S_D$ are very simple to measure by static test techniques, but the WT is measured by repeated loading procedure which requires relatively longer time and more efforts. Since these three properties are highly dependent upon the binder stiffness, it may be possible to estimate one property from another. Therefore, this study investigate the possibility of estimating the rutting characteristics (measured by WT test) by ITS or $S_D$ test, and the ITS by $S_D$. Because of binder stiffness effect, in the WT estimation by ITS, a tendency was observed for the higher ITS mixture to have the lower rut depth, giving $R^2{\fallingdotseq}$0.6, on the average. The ITS estimation by $S_D$ showed $R^2{\fallingdotseq}$0.64, and the WT estimation by SD showed $R^2{\fallingdotseq}$0.84, which is highest correlation among the three. Therefore, it was concluded that there is relatively good possibility of estimating WT result by $S_D$, and even though $R^2$ is somewhat low, there is some correlation between WT and ITS.

• International Journal of Highway Engineering
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• v.18 no.6
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• pp.97-104
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• 2016

OBJECTIVES : The objective of this research is to develop additives for the modification of Solvent DeAsphalting Residue (SDAR) to be used as pavement materials, and evaluate the performance of asphalt mixture manufactured using the SDAR modified by developed additives. METHODS : The SDAR generally consists of more asphaltenes and less oil components compared to the conventional asphalt binder, and hence, the chemical/physical properties of SDAR are different from that of conventional asphalt binder. In this research, the additives are developed using the low molecular oil-based plasticizer to improve the properties of SDAR. First, the chemical property of two SDARs is analyzed using SARA (saturate, aromatic, resin, and asphaltene) method. The physical/rheological properties of SDARs and SDARs containing additives are also evaluated based on PG-grade method and dynamic shear-modulus master curve. Second, various laboratory tests are conducted for the asphalt mixture manufactured using the SDAR modified with additives. The laboratory tests conducted in this study include the mix design, compactibility analysis, indirect tensile test for moisture susceptibility, dynamic modulus test for rheological property, wheel-tracking test for rutting performance, and direct tension fatigue test for cracking performance. RESULTS : The PG-grade of SDARs is higher than PG 76 in high temperature grades and immeasurable in low temperature grades. The dynamic shear modulus of SDARs is much higher than that of conventional asphalt, but the modified SDARs with additives show similar modulus compared to that of conventional asphalt. The moisture susceptibility of asphalt mixture with modified SDARs is good if, the anti-stripping agent is included. The performance (dynamic modulus, rutting resistance, and fatigue resistance) of asphalt mixture with modified SDARs is comparable to that of conventional asphalt mixture when appropriate amount of additives is added. CONCLUSIONS : The saturate component of SDARs is much less than that of conventional asphalt, and hence, it is too hard and brittle to be used as pavement materials. However, the modified SDARs with developed additives show comparable or better rheological/physical properties compared to that of conventional asphalt depending on the type of SDAR and the amount of additives used.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.314-321
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• 2016

Adapting the maintenance criteria of Seoul City pavement is not applicable for borough pavement due to differences between the pavement of Seoul city and the borough, such as priority of maintenance, traffic volume, thickness of pavement, and pavement deterioration rate by distresses. To develop an efficient and reasonable evaluation method of the Seocho borough pavement condition within a limited budget, this study suggested the borough pavement condition evaluation model based on the PMS (Pavement Management System) of Seoul Metropolitan SPI (Seoul Pavement Index). The SPI was modified to predict the remaining life and determine the proper maintenance method for the pavement in Seocho borough. This was suggested to reflect the rate of the designed performance life and field performance life of pavement as well as the pavement condition at the stage of the completion of construction. Primary variables, such as crack, rutting and IRI in the final model affect the overall performance life due to their even composition. Therefore, the suggested model considering the lowered criteria, design performance factor, and construction factor can be used for the more efficient maintenance of Seocho borough pavement.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.1
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• pp.35-46
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• 2007

In the study digital imagery was used to examine asphalt concrete pavements. With digitally mastered-image information that was filmed with a video camera fixed on a car travelling on road at a consistent speed, a road surface management system that can gain road surface information (Crack, Rutting, IRI) was developed using an object-oriented language "Delphi". This system was designed to improve visualized effects by animations and graphs. After analyzing the accuracy of 3-D coordinates of road surfaces that were decided using multiple image orientation and bundle adjustment method, the average of standard errors turned out to be 0.0427m in the X direction, 0.0527m in the Y direction and 0.1539m in the Z direction. As a result, it was found to be good enough to be put to practical use for maps drawn on scales below 1/1000, which are currently producted and used in our country, and GIS data. According to the analysis of the accuracy in crack width on 12 spots using a digital video camera, the standard error was found to be ${\pm}0.256mm$, which is considered as high precision. In order to get information on rutting, the physically measured cross sections of 4 spots were compared with cross sections generated from digital images. Even though a maximum error turned out to be 10.88mm, its practicality is found in work efficiency.