• Title/Summary/Keyword: 포장법

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Finite Element Analysis of Planar Effect on the Concrete Pavements (유한 요소법에 의한 콘크리트 포장 구조의 평면 거동연구)

  • Jo, Byung Wan
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.14 no.5
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    • pp.1091-1096
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    • 1994
  • Since horizontal movements due to shrinkage and thermal gradients in concrete pavements involve no actual load, the stresses induced will be those due to closing of the pavement joints and subbase friction. Consequently, complete derivations of stiffness matrix and equivalent nodal loads due to planar effects on the concrete pavements was throughly undertaken using the finite rectangular elements with two degrees of freedom at each node. The numerical example shows that the tensile stress induced in a pavement due to concrete shrinkage might be negligible except at very long slab and very high coefficient of frictions. However the stresses in conjunction with principal traffic loads might cause cracking problems.

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Evaluating a Load Limit on Heavy Vehicles in Flexible Pavements (아스팔트 포장구조체에 대한 중차량 제한하중 평가)

  • Park, Seong-Wan;Hwang, Jung Joon
    • 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.

Sensor Design for Chlorophyll Contents and Luxuriance of Rice Using Spectrum Analysis (분광분석법을 이용한 벼 엽록소 함량 및 번무량 센서 설계)

  • 성제훈;정선옥;이동현;서상룡
    • Proceedings of the Korean Society for Bio-Environment Control Conference
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    • 1999.11a
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    • pp.75-78
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    • 1999
  • 근래 들어 농업생산기술분야에서 변량적 포장 작물관리를 의미하는 정밀농업이라는 단어가 자주 등장한다. 정밀농업은 80년대 초반 미국에서 시작된 농법으로 정밀농업(precision farming or precision agriculture), 처방농업(prescription farming), 국부 특성에 맞는 작물관리(site-specific farming/management), 변량형 농업(variable rate agriculture) 등의 다양한 명칭으로 불리운다. 정밀농업의 중심과제는 포장내의 변이(variation), 즉, 토양의 이ㆍ화학 특성과 작물의 생육ㆍ수량에 나타나는 포장내의 불균형을 어떻게 평가하고 이를 기준으로 하여 어떻게 포장ㆍ작물관리를 수행하는가 하는 점이다. (중략)

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Evaluation of Subgrade Stiffness using Pressuremeter Test (공내재하시험에 의한 포장하부기초 강성도 평가)

  • Lim, Yu-Jin;Hai, Nguyen Tien;Jang, Duk-Sun
    • International Journal of Highway Engineering
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    • v.6 no.2 s.20
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    • pp.25-36
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    • 2004
  • The pressuremeter test can be used as an effective tool for evaluating stiffness of lower pavement layers including subgrade and subbase. At present, the most practical and applicable methods for evaluation of the stiffness of the subgrade and subbase are PBT and CBR in Korea. However, these methods have inherent drawbacks and large variabilities of test results themselves. In this study, an evaluation method and a test procedure that can be used for decision of pavement stiffness using pressuremeter were developed. The obtained results representing stiffness of the subgrade and subbase can replace PBT's soil reaction value k and CBR in design methods. It is found that the developed procedure based on the pressuremeter can provide an effective correaltion between the PBT's soil reaction value k and PMT's reloading modulus ($E_R$).

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Development of the Permanent Deformation Prediction Model of 19mm Dense Grade Asphalt Mixtures (19mm 밀입도 아스팔트 혼합물의 소성변형 예측 모델 개발)

  • Park, Hee-Mun;Choi, Ji-Young;Park, Seong-Wan
    • International Journal of Highway Engineering
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    • v.7 no.4 s.26
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    • pp.1-8
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    • 2005
  • Permanent Deformation is one of the most important load-related pavement distresses in asphalt pavements. The Korean Pavement Design Guide currently being developed adopted the mechanistic-empirical approach and needed the pavement distress prediction models. This study intends to develop the model for prediction of permanent deformation in the asphalt layer and estimate the pavement performance. The objectives of this paper are to figure out the factors affecting the permanent deformation and then develop the permanent deformation prediction model for asphalt mixtures. The repeated triaxial load test was Performed on the 19mm dense graded asphalt mixture with variation of temperature and air void. Results from the laboratory tests showed that temperature and air void in asphalt mixtures have significantly influenced on the factors in prediction model. The permanent deformation prediction model for 19m dense grade asphalt mixtures has been developed using the multiple regression approach and validated the proposed permanent deformation prediction model.

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