• 한국도로학회논문집
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• 제14권6호
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• pp.25-35
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• 2012

PURPOSES : Hollows are easily made, and bearing capacity can be lowered near underground structures because sublayers of pavement settle for a long time due to difficult compaction at the position. If loadings are applied in this condition, distresses may occur in pavement and, as the result, its lifespan can decrease due to the stress larger than that expected in design phase. Although reinforced slab is installed on side of box culvert to minimize the distresses, length of the reinforced slab is fixed as 6m in Korea without any theoretical consideration. The purpose of this paper is investigating the behavior of concrete pavement according to the cover depth of the box culvert ad the length of the reinforced slab. METHODS : The distresses of concrete pavement slabs were investigated and cover depth was surveyed at position where the box culverts were located in expressways. The concrete pavements including the box culverts were modeled by finite element method and their behaviors according to the soil cover depth were analyzed. Wheel loading was applied after considering self weight of the pavement and temperature gradient of the concrete pavement slab at Yeojoo, Gyeonggi where a test road was located. After installing pavement joint at various positions, behavior of the pavement was analyzed by changing the soil cover depth and length of the reinforced slab. RESULTS : As the result, the tensile stress developed in the pavement slab according to the joint position, cover depth, and reinforced slab length was figured out. CONCLUSIONS : More reasonable and economic design of the concrete pavement including the box culvert is expected by the research results.

• 한국도로학회논문집
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• 제16권6호
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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.

• 한국도로학회논문집
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• 제18권2호
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• pp.83-90
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• 2016

PURPOSES : Nowadays, cavity phenomena occur increasingly in pavement layers of downtown areas. This leads to an increment in the number of potholes, sinkholes, and other failure on the road. A loss of earth and sand from the pavement plays a key role in the occurrence of cavities, and, hence, a structural-performance evaluation of the pavement is essential. METHODS: The structural performance was evaluated via finite-element analysis using KPRP and KICTPAVE. KPRP was developed in order to formulate a Korean pavement design guide, which is based on a mechanical-empirical pavement design guide (M-EPDG). RESULTS: Installation of the anti-freezing layer yielded a fatigue crack, permanent deformation, and international roughness index (IRI) of 13%, 0.7 cm, and 3.0 m/km, respectively, as determined from the performance analysis conducted via KPRP. These values satisfy the design standards (fatigue crack: 20%, permanent deformation: 1.3 cm, IRI: 3.5 m/km). The results of FEM, using KICTPAVE, are shown in Figures 8~12 and Tables 3~5. CONCLUSIONS: The results of the performance analysis (conducted via KPRP) satisfy the design standards, even if the thickness of the anti-freezing layer is not considered. The corresponding values (i.e., 13%, 0.7 cm, and 3.0 m/km) are obtained for all conditions under which this layer is applied. Furthermore, the stress and strain on the interlayer between the sub-grade and the anti-freezing layer decrease gradually with increasing thickness of the anti-freezing layer. In contrast, the strain on the interlayer between the sub-base and the anti-freezing layer increases gradually with this increase in thickness.

• 한국도로학회논문집
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• 제7권2호
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• pp.23-31
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• 2005

본 연구는 장수명 아스팔트 포장 공법개발 연구의 일환으로 포장수명을 40년이상 지속시킬 수 있는 단면설계를 수행하였다. 본 연구의 목적은 포장체의 장수명화를 위하여 효과적이고 간편하게 포장체의 각층 단면두께 및 탄성계수를 결정하는 절차를 제시함에 있다. 포장체의 유한요소 해석을 통하여 장수명 아스팔트포장의 가상데이터베이스를 구축하였다. 이 가상데이터베이스는 포장체 각 층의 두께, 탄성계수 및 포장체 내의 처짐, 응력 및 변형률을 포함하고있다. 구축된 데이터베이스를 이용하여 포장의 장수명에 필요한 한계변형률을 만족하는 포장의 단면을 제시하였다. 연구결과, 총 아스팔트층의 두께가 410mm보다 큰 경우에는 포장층의 각층의 두께나 재료의 특성과 관계없이 항상 장수명 아스팔트 포장으로 간주할 수 있으나, 250mm보다 작을 경우에는 장수명 아스팔트 포장에서 제외되었다. 총 아스팔트층의 두께가 250mm보다 크고 410mm보다 작은 경우에는 장수명 아스팔트 포장 조건에 만족하기 위한 포장층 두께와 탄성계수값을 결정할 수 있는 절차를 제시하였다.

• 한국도로학회논문집
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• 제20권3호
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• pp.27-37
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• 2018

PURPOSES : The objective of this study is to develop a pavement rehabilitation decision tree considering current pavement condition by evaluating severity and distress types such as roughness, cracking and rutting. METHODS : To improve the proposed overall rehabilitation decision tree, current decision tree from Korea and decision trees from other countries were summarized and investigated. The problem when applying the current rehabilitation method obtained from the decision tree applied in Seoul was further analyzed. It was found that the current decision trees do not consider different distress characteristics such as crack type, road types and functions. Because of this, different distress values for IRI, crack rate and plastic deformation was added to the proposed decision tree to properly recommend appropriate pavement rehabilitation. Utilizing the 2017 Seoul pavement management system data and considering all factors as discussed, the proposed overall decision tree was revised and improved. RESULTS :In this study, the type of crack was included to the decision tree. Meanwhile current design thickness and special asphalt mixture were studied and improved to be applied on different pavement condition. In addition, the improved decision tree was incorporated with the Seoul asphalt overlay design program. In the case of Seoul's rehabilitation budget, rehabilitation budget can be optimized if a 25mm milling and overlay thickness is used. CONCLUSIONS:A practical and theoretical evaluation tool in pavement rehabilitation design was presented and proposed for Seoul City.

• 한국안전학회지
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• 제21권6호
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• pp.82-87
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• 2006

The existing raised pavement marker, however, have some limitations. Most of them are square-shaped which makes only forward and backward retro-reflection, their orientation can be easily changed by impact of vehicle, and the surface reflector can be readily contaminated leading poor functioning. In addition, maintenance for broken raised pavement marker is not easy. The purpose of the study is to design and manufacture a new and improved type of raised pavement marker. The new raised pavement marker has round-shaped upper structure. Its body was separated from the holder and the reflector was surrounded by acrylic cover. We tested performances of the constituent parts, optimum load after installation, and reflection efficiency. The new raised pavement marker will be an initiation of studies on the improvement of the shape and performance of raised pavement markers.

• 한국지반공학회지:지반
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• 제7권1호
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• pp.15-32
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• 1991

최근 선진각국은 회복탄성계수를 적용한 포장 설계.해석법의 적용을 확대해 나가고 있다. 특히, 1986년 AASHTO도로 포장구조설계지침의 변경이후 다양한 포장재료에 대한 합리적 인 시험 방법의 정립 및 Mn특성규명에 대한 연구들이 활발히 수행되고 있다. 따라서 본 연구에서는 가까운시일내 에 우리나라에서도 MR적용포장설계, 해석법의 적용이 불가피함을 고려하여, 이에 필요한 가장 기 본 적인 내용이라 할 수 있는국내 여건에 적합한 노상토의 Mr시험 방법의 정립, 국내 노상토의 Mr특성 및 MR-CBR상관관계에 대해서 논의하였다.

• 한국조경학회지
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• 제34권2호
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• pp.18-25
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• 2006

This study aims to measure and to analyze the thermal environment characteristics of the various permeable pavement materials such as grass pavement (GREEN BLOCK PARK), stone and grass pavement (GREEN BLOCK STEP), stone pavement (GREEN BLOCK MOSAIC) and wood pavement (WOOD BLOCK) under the summer outdoor environment. The thermal environment characteristics measured in the study includes the changes of surface temperature during the day, changes of the temperature on each pavement layer, and long and short wave radiation of each pavement surface. The experimental condition is based on the data on the hottest temperature (August 5, 2005, $34.0^{\circ}C$) of the you. Some of main findings are: 1) The heat environment was worse on the wood pavements than on the stone pavement. This is mainly due to the low albedo of the wood pavements (0.37) while the albedo value of stone pavements is 0.41. Small heat capacity of the wood pavements also contributes to this difference. 2) The heat environment was worse on the stone pavements than on the turf pavements. This was mainly due to the evapotranspiration of the plant growth layer of the turf pavements. 3) The peak surface temperature was the highest on the wood pavements ($56.1^{\circ}C$). The peak surface temperatures on the stone pavements, the stone-grass pavements and the grass pavements were $43.1^{\circ}C,\;40.1^{\circ}C\;and\;37.9^{\circ}C$, respectively. 4) To improve the thermal environments in the urban area, it is recommended to raise the albedo of the pavements by brightening the surface color of the pavement materials. Further studies on the pavement materials and the construction methods which can enhance the continuous evapotranspiration from the pavements surface are needed.

• 한국도로학회논문집
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• 제14권3호
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• pp.15-24
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• 2012

역학적-경험적 포장설계 프로그램 중에서, 미국 AASHTO 설계법을 기초로 개발된 MEPDG는 교통량, 기상, 재료물성, 포장구조 등을 입력변수로 하여 기술자가 최적의 대안을 찾도록 한다. 하지만 MEPDG에서 기술적 문제가 발견되고 있기 때문에 이를 해결하여 프로그램을 개선하기 위한 노력이 계속되고 있다. 한편, 국내에서도 KPRP 연구과제에서 역학적-경험적 포장설계 프로그램이 개발되어 왔다. 이 한국형 포장설계 프로그램을 더욱 합리적으로 개발하고 개선하기 위해서는 이미 사용되고 있는 MEPDG를 분석하여 서로 비교할 필요가 있다. 콘크리트 포장설계의 경우, 피로균열은 다른 공용성 인자와는 달리 매우 복잡한 로직을 통해 예측된다. 따라서 본 논문에서는 MEPDG 버전 0.5, 버전 1.0, 그리고 버전 1.1의 피로균열 전이함수를 분석하였다. 그리고 버전별 MEPDG와 KPRP 입력변수들의 누적피로손상에 대한 민감도를 서로 비교하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.611-616
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• 2013

Nowadays concrete pavement is increasing, since it is more durable than asphalt pavement. And the concrete pavement with lateral rain groove may induce high level of concrete whine noise as pure tone. In this paper, the design factor for good concrete whine noise is considered in view of tire pattern and structure design. In respect of tire pattern design, the tire having a cap tread with high center part stiffness and low shoulder part stiffness shows best concrete whine noise performance. And in respect of tire structural design, the tire with a thick center part of cap tread and low tread part stiffness show best concrete whine noise performance.