• International Journal of Highway Engineering
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• v.19 no.2
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• pp.75-85
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• 2017

PURPOSES : The purpose of this study was to determine the optimum mix design of the content of 100 % reclaimed asphalt pavement (RAP) for spray injection application with different binder types. METHODS : Literature review revealed that spray injection method is the one of the efficient and economical methods for repairing a small defective area on an asphalt pavement. The Rapid-Setting Polymer modified asphalt mixtures using two types of rapid setting polymers-asphalt emulsion and a quick setting polymer asphalt emulsion-were subjected to the following tests to determine optimum mix designs and for performance comparison: 1) Marshall stability test, 2) Retained stability test, 3) Wet track abrasion test, and 4) Dynamic stability test. RESULTS and CONCLUSIONS : Type A, B, and C emulsions were tested with different mix designs using RAP aggregates, to compare the performances and determine the optimum mix design. Performance of mixtures with Type A emulsion exceeded that of mixtures with Type B and C emulsion in all aspects. In particular, Type A binder demonstrated the highest performance for WTAT at low temperature. It demonstrated the practicality of using Type A mixture during the cold season. Furthers studies are to be performed to verify the optimum mix design for machine application. Differences in optimum mix designs for machine application and lab application will be corrected through field tests.

• Journal of the Korean GEO-environmental Society
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• v.13 no.2
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• pp.67-73
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• 2012

Asphalt pavement waste can be recycled by crushing and heating methods with additional virgin materials and additives. In this study, a new additive using Sasol wax and Polyolefin elastomer was used for improving the quality of the Superior recycled asphalt pavement(SRP). Additive was added into the recycled mixture by 1.5% and 3% of binder content in order to have PG 70-22 and PG 76-22. Both mixtures were tested by Marshall apparatus, indirect strength testing methods, toughness testing methods, moisture susceptibility testing methods and wheel tracking testing methods. Test results met the standards of KS F 2349 and GR F 4005. Through research, it was found that these special recycled mixtures could be applied for the surface and base course of heavy traffic roads or equivalents. About 13,000 tons of the recycled mixture has been applied on Seoul Olympic road to provide new road to Hangang park for Seoul citizens.

• International Journal of Highway Engineering
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• v.17 no.1
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• pp.17-24
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• 2015

PURPOSES : Recently, crack, rutting, and stripping problems from the surface of asphalt pavements in National highway are observed and they affect the drivers to feel uncomfortable on the road. Surface treatments are recommended to use in distressed pavements due to cost-effective, and improvement of surface performance. The purpose of this study is to evaluate the performance of micro-surfacing and polymer slurry seal treatments for distressed asphalt pavements. METHODS : Surface conditions and friction resistance are evaluated for asphalt pavements treated with micro-surfacing and polymer slurry seal mixes in National highway 30 line and 34 line. Visual observation is conducted and surface performance is measured by PES (Performance Evaluation Surveyor) in terms of crack ratio, rutting and IRI(International Roughness Index). BPN(British Pendulum Number) is measured by BPT(British Pendulum Tester) to evaluate the friction resistance in the field. RESULTS : The surface evaluation results are presented for asphalt pavement treated with micro-surfacing and polymer slurry seal treatments in National highway 30 line and 34 line. Based on the visual observation, micro-surfacing and polymer slurry seal treatments show better improvements in terms of cracks and stripping. Based on the surface conditions measured by PES vehicle, the surface performance of micro-surfacing treatments improves from 53.3% to 54.2% and the surface performance of polymer slurry seal treatments improves from 21.6% to 59.7%. However, the friction resistance of both micro-surfacing and polymer slurry seal treatments decreases from 2.5% to 6.7%. Further, it should be verified to produce the surface exposed with aggregates during the construction process of both treatment methods in the field. CONCLUSIONS : Based on the performance evaluation results in the filed, the surface performance of asphalt pavement treated with micro-surfacing and polymer slurry seal treatments improves from 21.6% to 59.7%. While, the friction resistance of asphalt pavement treated with micro-surfacing and polymer slurry seal treatments does not improve. It can be concluded that current micro-surfacing and polymer slurry seal treatments would improve surface performance but would not improve the friction resistance.

• International Journal of Highway Engineering
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• v.12 no.2
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• pp.81-90
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• 2010

This paper describes the results of laboratory and field performance tests on the polymer modified asphalt binder and mixtures developed in this study for porous asphalt pavements. Various physical and mechanical laboratory tests including DSR and BBR tests are performed for two types of modified binders, and one type of binder is selected based on the binder testing results. Mix designs are conducted for the selected asphalt binder and a Japanese modified binder, respectively. Various performance tests including fatigue tests, wheel tracking tests, and moisture susceptibility tests are conducted for the domestic and Japanese porous asphalt mixtures. Test results indicate that the overall performance characteristics of the domestic mixture are similar to or better than those of the Japanese mixture. Based on the laboratory testing results, the domestic porous mixture is applied to a field test section. Periodic field investigations are conducted to evaluate the changes in noise level and air voids with time. The road noise analysis shows that the noise levels of the porous pavement keep increasing and, after two years, are similar to those of SMA pavements.

• 한국도로학회:학술대회논문집
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• 2010.09a
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• pp.79-84
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• 2010

• 한국도로학회:학술대회논문집
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• 2001.10a
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• pp.93-99
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• 2001

• International Journal of Highway Engineering
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• v.14 no.4
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• pp.9-18
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• 2012

PURPOSES : This study evaluated the field applicability and laboratory performance of warm-mix asphalt (WMA) as an alternative technology in asphalt pavement. METHODS : The pilot road using two different types of WMA mixture and one HMA mixture was constructed in Waegwan-Seokjeok road construction site and the mixtures were sampled at the asphalt plant for laboratory testings. The field applicability was assessed in environmental aspects, such as $CO_2$ emission, and in aspects of constructibility using the existing equipment and procedure, i.e., thickness and density measurement. The laboratory testings included the moisture susceptibility test by AASHTO T283, dynamic modulus test, triaxial repeated load permanent deformation test, and the fatigue test. RESULTS : The temperatures for production and compaction of WMA were $20{\sim}30^{\circ}C$ lower than those for HMA and therefore, the noxious gas emission were significantly reduced. The field density of WMA pavements was similar or better than that of HMA pavement. From the laboratory testings, it was found that WMA mixtures exhibit comparable performance to HMA mixture in moisture susceptibility, permanent deformation, and fatigue performance. CONCLUSIONS : With these results, it would be concluded that WMA could replace the existing HMA technology without any significant issue. To support this conclusion, it is necessary to track the long-term performance of WMA in pilot road.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.93-101
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• 2011

The evaluation of various color coating methods for color maintenance of color asphalt pavement is conducted using the laboratory and field tests on the bus lane. The surface of color asphalt constructed on the bus lane is deteriorated such as changing color and decoloration and abrasion due to the passing of the traffic and time. The total of 9 coating methods were evaluated in this study. The laboratory tests included Ultra violet test, adhesion test and Taber abrasion test and the field tests were british pendulum test and visual survey. The results of tests showed that the different methods showed the their own engineering characteristics and it is dependant upon the main material used. The rubber epoxy material for the main material showed the satisfactory result among the methods tested. However, the performance of the coating methods after 100days are not satisfactory, decoloration, abrasion and peeling up are investigated and need to be studied for the further application in the field.

• International Journal of Highway Engineering
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• v.18 no.6
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• pp.131-136
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• 2016

OBJECTIVES : The objective of this research is to determine the integrity of pavement structures for areas where voids exist. Furthermore, we conducted the study of voided-area analysis and remaining life prediction for pavement structures using finite element method. METHODS : To determine the remaining life of the existing voided areas under asphalt concrete pavements, field and falling weight deflectometer (FWD) tests were conducted. Comparison methods were used to have better accuracy in the finite element method (FEM) analysis compared to the measured surface displacements due to the loaded trucks. In addition, the modeled FEM used in this study was compared with well-known software programs. RESULTS : The results show that a good agreement on the analyzed and measured displacements can be obtained through comparisons of the surface displacement due to loaded trucks. Furthermore, the modeled FEM program was compared with the available pavement-structure software programs, resulting in the same values of tensile strains in terms of the thickness of asphalt concrete layers. CONCLUSIONS : The study, which is related to voided-area analysis and remaining life prediction using FEM for pavement structures, was successfully conducted based on the comparison between our methods and the sinkhole grade used in Japan.

• International Journal of Highway Engineering
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• v.17 no.4
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• pp.33-40
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• 2015

PURPOSES: Evaluation of the wind speed effect on the temperature drop of an asphalt mixture during construction, by using the transient heat transfer theory and dominant convective heat transfer coefficient model. METHODS: Finite difference method (FDM) is used to solve the transient heat transfer difference equation numerically for various wind speeds and initial temperature conditions. The Blasius convective heat transfer coefficient model is adapted to account for the effect of wind speed in the temperature predictions of the asphalt mixture, and the Beaufort number is used to select a reasonable wind speed for the analysis. As a function of time and depth, the temperature of the pavement structure is predicted and analyzed for the given initial conditions. RESULTS : The effect of wind speed on the temperature drop of asphalt mixture is found to be significant. It seems that wind speed is another parameter to be accounted for in the construction specifications for obtaining a better quality of the asphalt mixture. CONCLUSIONS: It is concluded that wind speed has a significant effect on the temperature drop of the asphalt layer. Although additional field observations have to be made to reflect the effect of wind speed on the construction specifications, it appears that wind speed is a dominant variable to be considered, in addition to the atmospheric temperature.