• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.3D
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• pp.223-229
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• 2012

Skid resistance is defined as the friction between pavement surfaces and vehicle tires. Lower skid resistances were observed as the vehicle speeds the water film thicknesses were increased according to the analysis results using computer modeling. The lift force is calculated from the analysis results and depends on vehicle speeds and the water film thickness. A modified IFI(international friction index) skid resistance prediction model was developed to reduce the differences between the IFI resistance prediction model and the actual skid resistance. The correlation analysis results between the IFI prediction model and the actual skid resistance revealed that the $R^2$ using the modified IFI prediction model was 0.64 whereas the $R^2$ using the conventional IFI prediction model was 0.49. This presents the modified prediction model is better than the conventional one. An improved precise prediction model is to be obtained if water film thicknesses are considered in the modified prediction model.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.3
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• pp.1-7
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• 2009

In order to use recycled aggregate as pavement base or subbase materials, the US and many other European countries have started research since the early 1980s. Korea also had a recycle idea as a plan for the vast amount of construction wastes due to the downtown renovation in the 1990s, but was not put into practical use. After the resources saving and recycle expedition law in 1994, wastes from construction sites that have more than a certain amount of construction budget were recycled as pavement base and subbase materials, but now, researches are being conducted to use them as paving materials. The use of construction wastes is meaningful in many ways. It helps the natural conservation and aggregate consumption, and also improves pavement performance. This research presents a development of cold-mixed reclaimed asphalt pavement materials using recycled aggregates.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.2
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• pp.277-283
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• 2016

Recently, the interests in three-dimensional design and BIM(Building Information Modeling) are increasing in civil engineering sector and the researches about three-dimensional design and quantity take-off methods for civil engineering structures have been conducted. However, these studies are just carried out the 3D design and quantity calculation of civil structures on the road or railway such as bridges and tunnels. The study on the quantity take-off methods and the evaluation of calculated results on the earth works should be performed in more detail. Based on these backgrounds in mind, the study was conducted the three-dimensional road design and evaluated the quantity take-off results on the earth works using 3D calculation method(average end area method, prismoidal method and composit method). The calculated quantity from composit method showed about 5% error of measuring efficiency than the average end area method, and when reporting the quantity calculation of earth works, it is necessary to specify the calculation method using quantity take-off of earth works.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.178-178
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• 2011

도로소음은 다양한 소음원에 의해 발생하며, 도로를 이용하는 사람과 도로 주변사람에게 큰 불편을 초래한다. 보다 쾌적한 환경을 원하는 현대인에게 있어 도로 소음의 경감은 중요한 환경 공해로 작용한다. 도로 소음을 줄이기 위해서는 여러 가지 방법이 있을 수 있으며, 이 중 도로 포장의 개선을 통해 도로 소음을 경감할 수 있으며, 이와 같은 포장을 저소음 포장이라고 한다. 저소음 포장은 주행하는 차량의 타이어와 노면이 마찰하면서 발생하는 소음을 최소화하기 위한 것으로 소음 발생의 메커니즘을 바탕으로 하고 있다. 저소음 포장중 가장 널리 사용되고 있는 방법은 공극을 늘리는 것이다. 약 20%의 공극은 타이어와 노면 사이의 에어펌핑음을 최소화 하며, 소리를 흡수하는 역할로 약 3dB의 소음 가소 효과가 있는 것으로 알려져 있다. 소음을 감소시키는 또 하나의 방법은 노면의 표면 조직을 매끈하게 하여 타이어와 노면의 충격음을 줄이는 방법이다. 노면의 평탄성을 개선하기 위해 포장에 사용되는 골재의 최대크기를 줄이는 소입경 포장을 소음 가소의 목적으로 유럽 등지에서 많이 사용되고 있다. 본 연구에서는 이와 같은 저소음 기능을 위해 공극률을 크게 하고 소입경 골재를 사용하는 소입경 저소음 포장의 현장 적용을 위한 배합 설계를 수행하였다. 소입경 저소음 포장의 최대 골재 크기는 현장 적용성과 경제성을 고려하여 10mm 골재를 사용하였으며, 수도권에서 입수한 4곳의 산지 골재를 분석하여 골재 합성 입도를 산정하였다. 10mm 저소음 포장의 골재 입도 범위는 공극률 15~18%를 목표로 하며, 이를 만족하기 위하여 배합 설계를 수행한 결과 5mm 통과 중량 백분율이 약 30%로 하는 개립도가 적당한 것으로 나타났다. 공극이 증가함에 따라 포장의 내구성 향상을 위해 사용된 고점도 바인더는 아스팔트 혼합물의 생산 및 시공온도를 증가시키게 된다. 또한 굵은골재의 비율이 높은 개립도 아스팔트 혼합물의 경우 운반과정과 포설 과정에서 온도가 빨리 떨어지는 단점이 있다. 이를 극복하기 위하여 중온 첨가제의 사용을 통해 생산 및 다짐온도를 낮추고자 하였다. 소입경 저소음 포장의 배합설계 과정은 배수성 포장의 배합설계 과정과 유사하나, 칸타브로 손실률과 흐름실험의 변곡점을 기준으로 할 경우, 칸타브로 손실률과 흐름 손실률이 매우 작아 변곡점을 판단하기 어렵기 때문에 칸타브로 손실률과 흐름 손실률의 기준 만족 여부로 판별하고, 최적 아스팔트 함량은 공극률을 기준으로 산정하는 것이 바람직할 것으로 판단된다. 중온 첨가제를 사용할 경우는 중온 첨가제로 인한 점도의 변화를 감안하여 혼합 및 다짐 온도를 결정하고 배합 설계를 수행하며, 중온 첨가제의 특성과 양에 따라 최적 아스팔트 함량이 변화하게 된다.

• Korean Journal of Environment and Ecology
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• v.25 no.5
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• pp.649-657
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• 2011

This study had targeted the Manjong Junction~Hongchun interchange section of Jungang highway in order to analyze the efficiency and improvement of the highway wild-life fences. Being analyzed wild-life fence as an effective facility for the prevention of road-kill, it had founded that the wild animals did not jump over even the two layer guardrail, concrete barrier and noise barrier, fence for rock fall. For the section with high road-kill decrease effect after installing the wild-life fence, the effect was higher at wild-life fence with the height of 1.0m where the door had not been installed and the well connected points of road facility than the area with fence height of 1.5m. The road-kill decrease effect was also high at the well managed areas even if the door has not been installed. Also, road-kill had occurred by concentrating around the end of wild-life fence after installing the fence, Moreover road-kill had also occurred around the cutting section. The door of wild-life fence had higher amount of road-kill occurrence as the installation interval was closer. it was analyzed that the door management has a lot of effect on road-kill decrease. The fence for rock fall, two layer guardrail and concrete barrier having the effect of wild-life fence installed on the road would have to be installed by connecting with wild-life fences through proper facility improvement. Although the door should not be installed if possible, it should be installed as automatic door or gravity door to prevent the door from leaving the door open. An escape route has to be formed for the prompt escape away from the road for the animals entered through the ending section of the fence. The eco-corridor has to be made by restoring the soil layer of dual purpose eco-corridor forming a planting area. Also, the dead body after the accident has to be disposed to the outer section of the road immediately in order to prevent the secondary road-kill by the predator from the road-kill. The fence has to be installed as 500m or longer in both ways, in other words 1,000m or longer, from the targeted spot of minimum accident prevention while connecting up to the bridge or box culvert, etc that are next road facilities if possible to guide wild animals safely to the eco-corridor.

• 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.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.3
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• pp.603-610
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• 2017

Various type of pavement deterioration such as crack, bumpy, pothole is rapidly increasing according to the accelerated environmental changes like heavy rainfall, frequent snowing, difference temperature, etc. Accident related to pothole that cause fatal traffic accidents has been increased more than five times over the next five years starting from 2008. As direct or indirect damage by pothole which caused injuries and car damages increases every year, quicker and more efficient management measures are necessary. This study presents the algorithm for materials quantity take-off. The algorithm was suggested by correlation in pothole size and area. Suggested algorithm were confirmed the validity through the 15 field survey in capital area. According to the results of survey, usually the residual materials at which 5~7 kg was generated decreased to 1~2 kg. It showed that automatic pothole detection system is expected not only to reduce materials and resources, but also to contribute to quality improvements of pavement through more accurate material take-off from the situation of constructing rely on their own judgement.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1143-1151
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• 2013

Reasonable methods are needed to predict the noise level of new/existing roads and to select means of noise reduction. In this study, the noise reduction effects of both soundproof walls and quiet pavements were predicted. The noise reduction effects of quiet pavements were predicted by measurement data obtained using the CPX method in test pavements. The noise reduction effect was predicted by KHTN program when applied to soundproof walls and quiet pavement. As a result, the predicted noise level was similar to the measured one. The design method was suggested by an economic analysis using noise benefit of predicted noise reduction. The research suggests that the optimum alternative has to be determined using noise prediction method and life-cycle cost analysis.

• Journal of the Society of Disaster Information
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• v.7 no.2
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• pp.87-95
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• 2011

The skid resistant of pavement surface is an important parameter since it is directly related to the traffic safety under moving vehicular loads. In particular, it should be considered as a major factor in pavement performance evaluations to reduce the traffic accident from vehicular sliding. In this study, a portable and an automatic skid resistance tests were used to evaluate the skid resistances of the in-situ pavements. The test results showed that the skid resistance of the conventional dense graded pavement was more noticeable than the other pavement types such as the drainage pavement and the stone mastic asphalt(SMA) pavement as the service life of pavement was increased.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.601-608
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• 2006

The important elements in pavement design criteria are the stress and strain distributions. To obtain reasonable stress and strain distribution, tire contact area and tire pressures are very important. In this study, finite element analysis was used to identify the three-dimension states using nonlinear tire contact pressure and measured tire contact area. Measured tire contact area was quite different from the assumed tire contact area, and it resulted in different strain states under the tire. At the surface course, considering tire rib and nonlinear tire pressure, the pavement response presented accurate data compared to the predicted one. However, at the binder course, tire effects were generally negligible and it showed that the predicted pavement response was different compared to the measured one.