PURPOSES : The use of hydrated lime or other liquid anti-stripping agents (ASA) is the most common method of improving the moisture susceptibility of asphalt mixes. ASAs are also known to have an anti-aging effect, according to several researchers. Therefore, the use of ASAs is expected to enhance the stability of asphalt pavements. The purpose of this study is to investigate the anti-aging effect of ASAs that are found in the domestic market. METHODS : In this study, an asphalt binder and a mixture mixed with typical domestic solid and liquid ASAs were prepared and aged to evaluate the physicochemical changes. A liquid additive developed by a Korean oil refinery was used as the liquid ASA, and hydrated lime was utilized as the solid ASA. The aging process of the asphalt was determined in the laboratroy based on previous studies to simulate the aging process inh te field. RESULTS : The result of the laboratory experiment indicates that both the solid and liquid ASAs have an anti-aging effect. Moreover, the liquid additive performed relatively better than the hydrated lime. CONCLUSIONS : If ASAs have an anti-aging effect in addition to the anti-stripping function, it is expected to improve the stability of the asphalt pavement significantly. However, few studies have been carried out on the anti-aging effect of ASAs found in the domestic market. In this study, we conducted a fundamental study on the anti-aging effect to help in the selection and use of ASAs in the domestic asphalt-paving industry.

PURPOSES:This study aimed to analyze the experimental and numerical behavior of warm mix asphalt pavement prepared using steel slag and RAP and to conduct economic analysis of pavement construction.METHODS :For developing high performance asphalt pavement, we performed three evaluations: fundamental analysis, experimental testing, and 3D finite element analysis. In particular, 3D finite element analysis was conducted on several pavement structures by adopting the results of experimental tests.RESULTS :Through the various evaluations, it was established that steel slag was effective for use as asphalt mixture aggregate. Moreover, asphalt mixture constituting steel slag and RAP demonstrated higher performance behavior compared with conventionally used asphalt mixture. Furthermore, based on the 3D FE modeling, we established that the developed asphalt pavement constituting steel slag and RAP can be utilized for thin layer pavement with comparable performance behavior.CONCLUSIONS:Warm mix asphalt pavement prepared using steel slag and RAP is more competitive and economic compared to hot-mix asphalt pavement. Moreover, it can be applied for preparing thin layer asphalt pavements with reasonable performance. The developed warm mix asphalt pavement prepared using steel slag and RAP can be an alternative pavement type with competitive performance based on the reasonable economic benefit it provides.

This study evaluated the performance of GFDL HiRAM, a fine resolution AGCM, in the simulation of GPI (Genesis Potential Index) of tropical cyclone and its temporal variation over the Western North Pacific (WNP). We analyzed the AMIP simulation by the AGCM for the 30-year (1979-2008) forced by observed sea surface temperatures as the lower boundary condition. Since GPI depends on the five large-scale environmental factors(850 hPa absolute vorticity, 700 hPa relative humidity, vertical wind shear, maximum potential intensity, and 500 hPa vertical velocity), the biases of the simulation are examined for these factors as well as GPI itself. The results are compared with the ECMWF Interim reanalysis (ERA-I), and the analyses show that both the mean spatial pattern and the seasonal cycle of GPI over the WNP are reasonably simulated by HiRAM. But the magnitude of GPI is significantly underestimated due to the combined contribution of negative biases in four factors excluding the low-level vorticity. It is demonstrated that the three leading modes of spatio-temporal variability of GPI in EOF analysis for ERA-I are associated with ENSO, climate change with long-term trends, and SST anomalies over the WNP. The response of GPI to ENSO is more or less captured by HiRAM, including the east-west shift of Typhoon genesis location. However, it is supposed that unrealistic response of GPI and its factors to La-Nina or eastern Pacific El-Nino is an important shortcoming of HiRAM. In addition, HiRAM fails to reproduce the characteristic spatiotemporal variation associated with the climate change mode of GPI. The key findings from this study provide helpful guidance for improvement of HiRAM.

기상청에서 제공하는 강우자료는 현재 ASOS(종관기상관측장비)와 AWS(자동기상관측시스템) 등이 대표적으로 존재하고 다양한 분야에서 이를 활용한 연구·분석이 이루어지고 있다. 특정지점에서의 기상조건을 탐색하기 위한 방법으로는 지역의 기상조건을 대표할 수 있는 관측소의 값을 이용하거나 일련의 내삽(Interpolation)방법을 통해 공간적인 분석이 이루어 질 수 있다. 하지만 이러한 방법으로는 분석을 위해 자료를 개량하고 추측을 통해야 한다는 한계점이 존재한다. 공간에 기반을 둔 분석을 위해 이러한 한계점을 개선하기 위해서는 일정한 규모의 격자자료가 필요할 것이라 판단된다. 기상청에서는 동네예보를 지원하기 위해 RSA(실황분석자료, Real State Analysis)자료를 생산하고 있다. 이는 KLAPS(초단기 기상분석 및 예측시스템) 재분석자료, 합성레이더 강우량, AWS 관측자료를 합성시켜 생산한 자료로써 5km×5km의 공간해상도를 가진 격자자료이다. 본 연구에서는 ASOS와 AWS, RSA 자료에서 제공되는 강우량과 환경부에서 제공되는 대기측정자료를 이용하여 서로 다른 성격의 기상자료에서 제공되는 기상조건의 변화가 대기오염망에는 어떠한 영향을 미치는지에 대해 분석하고자 한다. 이를 통해 지점(Point)자료와 격자(Raster)자료간에 분명한 차이가 존재한다면 산사태 지점, 교통사고 지점 등과 같이 위치 중심의 공간분석에서 비교적 정밀한 결과를 도출하는데 활용될 수 있을 것이라 기대된다.

We analyzed the impact of the heavy snowfall occurred from Feb. 10 to Feb. 14, 2011 on the inbound daily traffic volume of the Gangneung Highway Tollgate using time series regression models. We found that the maximum reduction rate of inbound highway tra˜c volume during the heavy snowfall period is 70%. °e inbound tra˜c volume increased steadily to normal inbound tra˜c volume after 2 to 4 days from the date when the snowfall stopped. The reason why 2 to 4 days are needed to reach normal inbound tra˜c volume is that it took substantial time to clear snow from the roads.