• Title/Summary/Keyword: 아스팔트 콘크리트

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A Fundamental Study on the Pullout Strength Equation of High Strength Anchor for Asphalt Pavement (아스팔트용 고강도 앵커시스템의 인발강도식 검토에 관한 기초적 연구)

  • Choi, Jaemin;Lee, Seungyong;Sung, Kitae;Han, Youngdoo
    • Journal of the Society of Disaster Information
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    • v.13 no.3
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    • pp.313-321
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    • 2017
  • In order to investigate the basic performance of the high strength anchor for asphalt road subjected to tensile load, the static pullout test was carried out and the pullout strength of the asphalt anchor was analyzed. In the pullout test, the depth of anchor, depth of pavement, diameter of anchor, type of anchor, experimental temperature, epoxy type and amount of anchor were used as test variables. As a result, the steel strength of asphalt anchor was 1.08 times higher than that of conventional concrete anchor, therefore it is considered appropriate to use the steel strength formula of concrete anchor for asphalt anchor. Compared with the proposed formula, the pullout load obtained from the test of the asphalt anchor was within ${\pm}10%$. The ratio of the projected area of the asphalt anchor is similar as that of the concrete anchor.

Performance of Constructed Facilities: Pavement Structural Evaluation of William P Hobby Airport in Houston, Texas

  • Kim, Sung-Hee;Jeong, Jin-Hoon;Kim, Nak-Seok
    • Journal of the Korean Society of Hazard Mitigation
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    • v.9 no.1
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    • pp.21-25
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    • 2009
  • The results of a recent case study for material characterizations and structural evaluation to design asphalt overlay thickness of William P Hobby airport in Houston, Texas are presented herein. The existing runway 12R-30L of Hobby airport consisted of thick asphalt overlay over Portland Cement Concrete (PCC) and the localized surface shoving as evident in the closure of surface groove has been observed recently. Using the field cored asphalt concrete mixtures, measurements of percent air voids, asphalt content and aggregate gradation were conducted to find out the causations of surface shoving and groove closure. The FAA layered elastic program, LEDFAA was utilized to evaluate pavement structural conditions for new asphalt overlay. Two different composition assumptions for existing pavement were made to evaluate the pavement as followings: 1) APC, Asphalt Concrete Overlay over PCC pavement and 2) AC, Asphalt Concrete pavement. Based on laboratory testing results, a ratio of percent passing #200 to asphalt content ranged 1.1 to 2.2, which is considered a high ratio and a tendency of tender mix design was observed. Thus, the localized surface shoving and groove closure of the runway 12R-30L could be attributed to the use of excessive fine contents and tender mix design. Based on the structural evaluation results, it was ascertained that the analysis assuming the pavement structure as AC pavement gives more realistic structural life when the asphalt overlay is thicker enough compared to PCC layer because the existing PCC pavement under asphalt overlay acts more like a high quality base material.

An Evaluation of Moisture Sensitivity of Asphalt Concrete Pavement Due to Aging (노화에 따른 아스팔트 콘크리트 포장의 수분민감성 평가)

  • Kim, Kyungnam;Kim, Yooseok;Kim, Nakseok
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.39 no.4
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    • pp.523-530
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    • 2019
  • Pavement distress and traffic accidents are caused by pot-hole. In addition, direct and indirect damages of road users are increasing, such as loss of life due to personal injury and damage to vehicles. Generally, the asphalt concrete pavements are continuously aging from the production process to the terminal performance period. Aging causes stripping due to cracks and moisture penetration and weakening the pavement structure to induce pot-hole. In this study, adhesion performance and moisture sensitivity were evaluated according to aging degree in order to investigate the effect of aging on asphalt pavement. As a result of the study, the viscosity of the asphalt binder was increased with aging and the bond strength of the aged was increased 2~3 times than that of the unaged. The results of accelerated aging test showed an increases in indirect tensile strength and the increase in the TSR (Tensile Strength Ratio) by 4.2~8.9 %. As a result, it is noted that the anti-stripping and adhesion performances of the aged asphalt concrete are improved compared to the unaged one under the aging conditions of asphalt binder coated on aggregates.

A Study on Fatigue Characteristics and Economic Analysis of Discharged Nylon Fiber-Reinforced Asphalt Concrete (폐나일론을 이용한 섬유보강 아스팔트 콘크리트의 피로특성 및 경제성 분석)

  • Baek, Ingyu;Park, Kisun;Kim, Nakseok
    • Journal of the Society of Disaster Information
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    • v.9 no.4
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    • pp.476-483
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    • 2013
  • In this study, discharged nylon fibers were added to asphalt concretes to be compared with fatigue life and analyzed in economic point of view. A four point bending fatigue test was conducted, and as a result, nylon fiber reinforced asphalt concretes that showed a 10percent increase in fatigue life compared to ordinary asphalt concrete. The economic analysis confirmed that the maintenance cost was decreased by 540 million won throughout the analyzing period. It is thought discharged nylon fiber reinforced asphalt will cause more economic and social effects than was shown by life cycle cost analysis.

Evaluation of Design Temperature for Asphalt Concrete in South Korea (남한의 아스팔트 콘크리트 설계온도 추정에 관한 연구)

  • Lee, Kwang Ho;Kim, Soo Il
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.12 no.2
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    • pp.77-85
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    • 1992
  • Layer material properties of asphalt concrete changes with climatic conditions. Pavement design and analysis should be performed in the representative climatic condition that gives standard physical properties of pavement layer materials. In this study, an evaluation procedure of pavement design temperature is proposed and programed based on damage effect analysis using fatigue failure criterion. Three regions, Seoul, Daegeon, and Pusan, are chosen to obtain the representative climatic data of South Korea. Domestic pavement design temperature is developed by applying the proposed algorithm to 6 domestic pavement section models with the respective regional climatic data. Asphalt concrete pavement failure criterion is also proposed for the condition of developed domestic pavement design temperature. The design temperature for the region of South Korea is estimated as $l7^{\circ}C$, which is converted to $23.6^{\circ}C$ for the AC surface layer temperature. It is found that the procedure to determine design properties of AC surface layer material at $20^{\circ}C$ gives overestimated results of AC moduli for the domestic pavement system. From the comparison study, it is also found that the estimated pavement design temperature is similar to the result of SHELL Design Chart.

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Evaluation of Flexible Pavement Layer Moduli Using the Depth Deflectometer and Flexible Pavement Behavior under Various Vehicle Speeds (아스팔트 콘크리트 포장구조체의 내부처짐에 의한 물성추정과 주행속도에 따른 거동분석)

  • Choi, Jun-Seong;Kin, Soo-Il;Yoo, Ji-hyung
    • International Journal of Highway Engineering
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    • v.2 no.1
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    • pp.135-145
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    • 2000
  • A new procedure needs to be developed to predict the dynamic layer properties under moving truck loads. In this study, a computer code to evaluate layer moduli of asphalt concrete pavement from measured interior deflections at various depths were developed and verified from numerical model tests. Interior deflections of the pavement are measured from Multi-Depth Deflectometer(MDD). It was found that errors between the given and backcalculated moduli in numerical analysis were less than 0.32% for several numerical models tested. When impact loads were used, a technique to determine the depth to virtual rigid base was proposed through the analysis of compressive wave velocity and impulse loading durations. It was found that errors between the given and backcalculated moduli in numerical analysis were less than 0.114% when virtual rigid base was considered in numerical analysis. The pavement behavior must be evaluated under various vehicle speeds when determining the dynamic interaction between the loading vehicle and pavement system. To evaluate the dynamic behavior on asphalt concrete pavement under various vehicle speeds, truck moving tests were carried out. From the test results with respect to vehicle speed, it was found that the vehicle speed had significant effect on actual response of the pavement system. The lower vehicle speed generates the higher interior deflections, and the lower dynamic modulus.

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Constitutive Modeling of Asphalt Concrete with Time-Dependent Damage Growth (손상이 증가하는 아스팔트 콘크리트의 점탄성 구성모델)

  • 이현종
    • Computational Structural Engineering
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    • v.10 no.4
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    • pp.229-238
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    • 1997
  • Mechanical behavior of asphalt concrete that accounts for viscoelasticity and damage evolution under cyclic loading conditions is modeled and presented in this paper. An elastic-viscoelastic correspondence principle in terms of pseudo variables is applied to separately evaluate viscoelasticity and time-dependent damage growth in asphalt concrete. A microcrack growth law, which is commonly employed in linear viscoelastic fracture mechanics, is successfully used for describing the damage growth in the body. A constitutive equation in terms of stress and pseudo strain is first established for controlled-strain mode, and then transformed to controlled-stress constitutive equation by simply replacing stress and pseudo strain with pseudo stress and strain. The transformed constitutive equation in terms of pseudo stress satisfactorily predicts the mechanical behavior of asphalt concrete all the way up to failure under controlled-stress modes.

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An Evaluation of Resistances in Porous Asphalt Concrete Mixtures due to Repeated Cyclic Freeze-Thawing (배수성 아스팔트콘크리트 혼합물의 반복 동결융해 저항성 평가)

  • Jo, Shin Haeng;Kim, Nakseok
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.1D
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    • pp.33-39
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    • 2012
  • More and more pavements are suffering from damage these days due to the below-zero winter temperatures and frequent snowfalls. From this research, the freeze-thawing mechanisms of pavements will be observed, and the freeze-thawing resistance of porous asphalt concrete mixture is to be evaluated according to various assessment methods. The investigation was conducted through applying rigid and flexible pavements to freeze-thawing resistance experiments, which include various experiments such as deformation rate measurements, Lottman tests, repeated cyclic freeze-thawing experiments, stripping resistance tests and so on. Test results revealed that the porous asphalt concrete had less deformations according to temperatures compared to dense-graded asphalt concrete due to the 20% void gap. In addition, according to the freeze-thawing repetition experiments which are effected by moisture, the porous asphalt concrete mixture showed superior resistance to repeated cyclic freeze-thawing compared to other asphalt concrete mixtures due to the drainage and the voids within the specimen.