• International Journal of Highway Engineering
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• v.8 no.1 s.27
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• pp.77-87
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• 2006

Dynamic stability (DS) in the wheel tracking (WT) test is used as a basic index of rut-resistance for asphalt mixtures. In general, the deeper rut depth is obtained from the weaker mixture, resulting in the lower DS value. On the other hand, the shallower rut depth is obtained from the stronger mixture, resulting in the higher DS. However, it is not always the case when the DS is calculated by the existing method because the DS is simply determined based on the slope at the final stage of the rut depth-cycle curve. Specifically, in the case of the depth-cycle curve showing a steeper slope in the early part but flatter slope in last part, the DS is calculated to be higher than the curve showing a ever-increasing slope throughout the test. As long as the last part of slope is flatter, the deeper final rut depth is evaluated to show a higher DS than the little final rut depth. Therefore, a reasonable method for DS evaluation need to be established. Several new methods were suggested by considering the early, middle and final parts of rut depth to determine a reasonable DS. The results have shown that those new methods have demonstrated a significant improvement in distinguishing similarly performing mixtures. The result also showed that $DS_2$ had better correlation with SD than any other methods , representing the rutting resistance of asphalt mixture very well. The new DS calculation method is relatively simple and easy to follow. More validatin study is required for practical application.

• International Journal of Highway Engineering
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• v.16 no.6
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• pp.105-113
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• 2014

PURPOSES: The objective of this paper is to select the confidential intervals by utilizing the second moment reliability index(Hasofer and Lind; 1974) related to the number of load applications to failure which explains the fatigue failure and rut depth that it indicates the permanent deformation. By using Finite Element Method (FEM) Program, we can easily confirm the rut depth and number of load repetitions without Pavement Design Procedures for generally designing pavement depths. METHODS : In this study, the predictive models for the rut depth and the number of load repetitions to fatigue failure were used for determining the second moment reliability index (${\beta}$). From the case study results using KICTPAVE, the results of the rut depth and the number of load repetitions to fatigue failure were deducted by calculating the empirical predictive equations. Also, the confidential intervals for rut depth and number of load repetitions were selected from the results of the predictive models. To determine the second moment reliability index, the spreadsheet method using Excel's Solver was used. RESULTS : From the case studies about pavement conditions, the results of stress, displacement and strain were different with depth conditions of layers and layer properties. In the clay soil conditions, the values of strain and stresses in the directly loaded sections are relatively greater than other conditions. It indicates that the second moment reliability index is small and confidential intervals for rut depth and the number of load applications are narrow when we apply the clay soil conditions comparing to the applications of other soil conditions. CONCLUSIONS : According to the results of the second moment reliability index and the confidential intervals, the minimum and maximum values of reliability index indicate approximately 1.79 at Case 9 and 2.19 at Case 22. The broadest widths of confidential intervals for rut depth and the number of load repetitions are respectively occurred in Case 9 and Case 7.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.783-796
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• 2006

Rut-resistance pavement is adopted to prevent pavement from plastic deformation since 1998. The objective of this paper is to investigate performance and economic efficiency between rut-resistance pavement and conventional hot-mix asphalt(HMA) on national highway. The pavement deterioration models incorporated in HDM-4 have been calibrated and adapted to local road conditions based on observed pavement rut-depth data. Based on calibration result of HDM-4, the economic evaluation including road agency cost and user cost is performed for 34 road pavement sections. Furthermore, we presented optimal timing for maintenance and performance levels subject to different budget. We found that rut-resistance pavement is performing better than conventional hot-mix asphalt in most road sections. Furthermore, we confirmed that the application of HDM-4 is useful for pavement project planning and evaluation. More investigation is needed to enlarge the scope of the pavement data and to explore more deeply socio-environmental cost and delay cost.

• International Journal of Highway Engineering
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• v.11 no.4
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• pp.25-31
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• 2009

In general, it is well known fact that the stone mastic asphalt (SMA) pavement has a high resistance against rutting. However, performance of SMA is not well measured by general method used in the laboratory. The objective of this study is to investigate an applicability of deformation strength ($S_D$) for performance estimation of SMA, and to find out the correlation between rut depth and dynamic stability, and $S_D$ of SMA. This study carried out wheel tracking test and Kim-test with optimum asphalt content (OAC) determined by mix design. The results indicated that the $S_D$ of SMA was very poorer than those of dense-graded asphalt mixtures. $S_D$ showed similar WT dynamic stability and rut-depth level. It was found that Kim-test was not reflected higher rutting resistance of SMA like as indirect tensile strength (ITS) test and Marshall stability test. Also, it was revealed that dynamic stability and rut-depth of WT had some problems to estimate rutting resistance of SMA mixtures.

• 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.

• 한국도로학회:학술대회논문집
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• 2005.11a
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• pp.127-132
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• 2005

• International Journal of Highway Engineering
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• v.8 no.1 s.27
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• pp.1-13
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• 2006

This paper is one of the studies for developing new methodologies for improving performance of hot-mix recycled asphalt mixtures. The objective of this study is to evaluate rut-resistance characteristics of recycled asphalt mixture which was prepared by newly developed mixing method. The new mixing method provided more sufficient rejuvenation of old binder of reclaimed asphalt pavement (RAP), making homogeneous binder viscosity level in a recycled mixture. Two aggregates (gneiss and granite), two RAP contents (15% and 30%) and two contents (none and 6%) of polymer modifier (LDPE) were used. Recycled mixture was prepared with two methods; method A and method F. To examine difference of binder oxidation level by type of material within a recycled mixture, Gel-permeation chromatography(GPC) analysis was performed on the binders mixed with coarse aggregates and matrix separately. Laboratory tests were performed for evaluation of rut resistance characteristics of each recycled mixture and these includes wheel tracking (WT) test and Kim test. Rut depth and dynamic stability were obtained from WT test and deformation strength $(S_D)$ was obtained from Kim test. The results of regression analysis was shown that correlation $(R^2)$ of F mixing mixtures was higher than one of A mixing mixtures. Therefore, F mixing mixtures showed more consistent rut resistance than h mixing mixtures.

• 한국도로학회:학술대회논문집
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• 2003.10a
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• pp.35-40
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• 2003

• International Journal of Highway Engineering
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• v.6 no.3 s.21
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• pp.37-46
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• 2004

This study was performed to establish valid methodology for determining dynamic stability(DS) of deformation-cycle curve which is obtained through wheel tracking(WT) test, the most widely used method for forecast of rutting tendency of asphalt mixture. Existing Korean and Japanese methods for DS are unrealistic and do not really reflect characteristics of rut resistance of asphalt concretes especially when the slope of deformation-cycle curve is stabilized at the end. It was proved that the new DS developed in this study reflected rut resistance characteristics better than existing methods. It is especially effective to distinguish the mixtures with high DR(depth of rut) but stable slope at the end of curve from the mixture with lower DR and continuous slope. The field evaluation must be followed to prove whether the mixture which shows a high DS value this method perform well in the filed.

• International Journal of Highway Engineering
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• v.20 no.4
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• pp.7-13
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• 2018

PURPOSES : In order to apply high-speed weigh-in-motion (HS WIM) systems to asphalt pavement, three high-durability asphalt concrete mixtures installed with a WIM epoxy are evaluated. METHODS : In this study, dynamic stability, number of loading repetitions to reach the rut depth of 1 mm, and rut depth measurements of three asphalt mixtures at $60^{\circ}C$ were compared using an Asphalt Pavement Analyzer (APA). Laboratory-fabricated material and field core samples were prepared and tested according to KS F2374. RESULTS : Through the laboratory tests, it was found that all three modified asphalt mixtures (stone-mastic, porous, and semi-rigid) with WIM epoxy showed favorable permanent deformation results and passed the dynamic stability criterion of 3000 loading repetitions per 1 mm. In addition, it was confirmed that the modified SMA mixtures cored from the field construction yields satisfactory rutting testing results using the APA. Finally, the epoxy used for the HS WIM installation shows good adhesion with the three asphalt mixtures and permanent deformation resistance.