고속도로 포장 장기 공용성 관측구간 데이터를 활용한 아스팔트 포장의 공용특성 분석

박희영,이정훈,윤영미,박준영,김형배 한국도로학회 2020 한국도로학회논문집 Vol.22 No.3

PURPOSES : The purpose of this study is to evaluate the performance characteristics of stone mastic asphalt (SMA) pavement by comparison with polymer modified asphalt (PMA) pavement and conventional asphalt pavement, to check the performance characteristics according to the pavement type, pavement materials, traffic volume, and environmental factors and to analyze the quality variation characteristics according to the pavement materials using data extracted from the database of the expressway long-term pavement performance. METHODS : Approximately 10% outlier data of pavement performance data were excluded in order to increase the reliability of the analysis results before evaluating the asphalt pavement performance. The performance model was developed through linear regression analysis by setting the performance period as the independent variable and the highway pavement condition index (HPCI) as the dependent variable. Descriptive statistic analysis of HPCI using the static package for social science (SPSS) tool and the analysis of variance was performed to identify the quality variation characteristics according to the pavement materials. The amount of de-icing agent and traffic level of service were classified as two levels in order to check the influence of traffic volume and environmental factors on the performance characteristics of the asphalt pavement. RESULTS : The tentative pavement performance lives were calculated at 19.3 years for new the SMA pavement (GPS-2), 14.3 years for the SMA overlay on the asphalt pavement (GPS-6), and 10.3 years for the SMA overlay on the concrete pavement (GPS-7). In case of the asphalt overlay, the tentative performance lives were calculated at 8.2 years for the PMA overlay on the asphalt pavement (GPS-6), 7.2 years for the PMA overlay on the concrete pavement (GPS-7), 7.2 years for the conventional asphalt overlay on the asphalt pavement (GPS-6), and 5.5 years for the conventional asphalt overlay on the concrete pavement (GPS-7). CONCLUSIONS : It was confirmed that the SMA pavement showed better performance and quality variation characteristics than the PMA and conventional asphalt pavement. The performance characteristics of the asphalt pavement (GPS-2) was better than the asphalt overlay pavement, and the asphalt overlay on the asphalt pavement (GPS-6) had better performance characteristics than the asphalt overlay on the concrete pavement (GPS-7). It was observed that the asphalt overlay on the asphalt pavement (GPS-6) was strongly influenced by the traffic volume and the asphalt overlay on concrete pavement (GPS-7) was strongly influenced by the traffic volume and de-icing agent.

한국형 포장관리시스템을 활용한 장수명 아스팔트 포장의 경제성 분석

도명식,권수안,백종은,최승현 한국도로학회 2016 한국도로학회논문집 Vol.18 No.4

PURPOSES : Long-life asphalt pavements are used widely in developed countries. In order to be able to devise an effective maintenance strategy for such pavements, in this study, we evaluated the performance of the long-life asphalt pavements constructed along the national highways in South Korea. Further, an economic evaluation of the long-life asphalt pavements was performed based on a life-cycle cost analysis. We aimed to devise a model for evaluating the performance of long-life asphalt pavements using the national highway pavement management system (PMS) database as well as for analyzing the economic feasibility of such pavements, in order to promote their use in South Korea. METHODS : The maintenance history and pavement performance data were obtained from the national highway PMS database. The pavement performances for a total of 292 sections of 10 lanes (5 northbound lanes and 5 eastbound lanes) of national highways were used in this study. Models to predict the performances of hot mix asphalt (HMA) and long-life asphalt pavements under two distinct traffic conditions were developed using a simple regression method. Further, the economic feasibility of long-life asphalt pavements was evaluated using the Korea Pavement Management System (KoPMS). RESULTS : We developed service-life prediction models based on the traffic volume and the equivalent of single-axle load and found that long-life asphalt pavements have service lives 50% longer than those of HMA pavements. Further, the results of the economic analysis showed that long-life asphalt pavements are superior in terms of various economic indexes, including user cost, delay cost, total cost, and user benefits, even though their maintenance cost is higher than that of HMA pavements. A comparison of the economic feasibilities of the various groups showed that group A is superior to HMA pavements in all aspects except in terms of the maintenance criterion (crack 20% or higher) as per the NPV index. However, the long-life asphalt pavements in group B were superior in terms of the maintenance criterion (crack 25% or higher) regardless of the economic feasibility. CONCLUSIONS: The service life of long-life asphalt pavements was found to be approximately 50% longer than that of HMA pavements, regardless of the traffic volume characteristics. The economic feasibility of long-life asphalt pavements was evaluated based on the KoPMS. The results of the economic analysis were the following: long-life asphalt pavements are exceptional in terms of almost all factors, such as user cost, delay cost, total cost, and user benefit; however, the exception is the maintenance cost. Further, the economic feasibility of the long-life asphalt pavements in group B was found to be better than that of the HMA pavements (crack 25% or higher).

LTPP-SPS : 섬유보강 아스팔트 포장의 구조적 성능 평가

전성일,김부일,김조순,임광수 한국도로학회 2008 한국도로학회논문집 Vol.10 No.4

In Korea-LTPP(Long Term Pavement Performance) project, the full depth asphalt pavement test sections are constructed on the national highway to evaluate the structural capacity of asphalt pavement reinforced with glass fiber. Truck loading test and FWD test were performed to measure the structural capacity of test sections. Test results showed that the reinforcement of glass fiber installed at between surface and intermediate asphalt layer decreased the strain at the bottom of surface layer and moved up the stress neutral axis in asphalt layer. As a result, the tensile stress was developed at the bottom of intermediate asphalt layer of reinforced asphalt pavement, while the compressive stress was developed at the bottom of intermediate asphalt layer of unreinforced asphalt pavement. On the other hand, the tensile strain at the bottom of asphalt base layer didn't show a difference between glass fiber reinforced and unreinforced pavements. From the FWD test, it was shown that the surface deflection of asphalt pavement reinforced with glass fiber decreased 24 percents comparing to that of unreinforced asphalt pavement. This shows that the reinforcement with glass fiber appears to improve the rutting resistance of asphalt pavement. In Korea-LTPP(Long Term Pavement Performance) project, the full depth asphalt pavement test sections are constructed on the national highway to evaluate the structural capacity of asphalt pavement reinforced with glass fiber. Truck loading test and FWD test were performed to measure the structural capacity of test sections. Test results showed that the reinforcement of glass fiber installed at between surface and intermediate asphalt layer decreased the strain at the bottom of surface layer and moved up the stress neutral axis in asphalt layer. As a result, the tensile stress was developed at the bottom of intermediate asphalt layer of reinforced asphalt pavement, while the compressive stress was developed at the bottom of intermediate asphalt layer of unreinforced asphalt pavement. On the other hand, the tensile strain at the bottom of asphalt base layer didn't show a difference between glass fiber reinforced and unreinforced pavements. From the FWD test, it was shown that the surface deflection of asphalt pavement reinforced with glass fiber decreased 24 percents comparing to that of unreinforced asphalt pavement. This shows that the reinforcement with glass fiber appears to improve the rutting resistance of asphalt pavement.

Analysis of Temperature Distribution of Concrete Base Layer by Mixture and Thickness of Asphalt Overlay

Jun Young Park,Han Jin Oh,Hyung Bae Kim,Sung Woo Ryu 한국도로학회 2018 한국도로학회 학술대회 발표논문 초록집 Vol.2018 No.05

In Korea, concrete pavements were first applied to highways in 1981 and as a result of continued increase in length over the past years, 2,592 km of concrete pavement network is currently in service, of which 1,399 km(54%) of concrete pavements is 10 years or older, and 233km(9%) is 20 years or older. The length of concrete pavement sections nationwide has been steadily on the rise every year (EXTRI, 2017). Approximately 54% of current concrete pavement highway network will reach the service life limit in 2025 which means around 660 billion won is needed for future pavement repair project (EXTRI, 2017). Given that concrete pavements beyond design life still have a remaining service life, it is economically advantageous to repair them before reconstruction. Asphalt overlays are a major repair method for older concrete pavements. Depending on the concrete pavement condition, thickness and mixture of asphalt overlays are determined. Service life of asphalt overlays varies by the presence, time and size of cracks in existing concrete pavements and reflecting crack at joints. Temperature change of concrete pavement is among the major reaction parameters of reflecting crack. Reflecting crack develops when asphalt bottom-up cracking by longitudinal shrinkage and expansion due to temperature change of the concrete base layer, top-down cracking by temperature difference between top and bottom of concrete, and shear stress by traffic loading are combined (Baek, 2010). Crack and joint behaviors of concrete pavement vary between the base layer and the concrete surface of composite pavement system, and different conductivity by mixture and thickness of asphalt overlay leads to temperature change of concrete base course. This study measured temperatures of each layer of diverse composite pavements in place on site and analyzed differences in temperature change of concrete base layer depending on mixture and thickness of asphalt overlays. Overlay thickness parameters were 5cm and 10cm, two values most widely used, while mixture parameters were SMA and porous asphalt. Based on temperature change of concrete surface, this study also evaluated the difference of temperature change in concrete base layer with an asphalt overlay on top. Findings from this study are expected to be utilized for studies on mechanism and modeling of reflecting crack in old concrete pavements with asphalt overlays.

순환골재를 표층 재료로 사용한 아스팔트 콘크리트 포장의 현장 공용성 평가

김부일 한국아스팔트학회 2023 한국아스팔트학회지 Vol.13 No.1

This study is to evaluate the field performance of reclaimed asphalt pavement mixed with 70.0% of recycled aggregate. Mix-design was conducted to determine the proper aggregate gradation and optimum asphalt contents. Reclaimed asphalt mixtures were produced to meet the criteria of WC-5 described on KS F 2337 and mixed with 1.27% of asphalt, 26.5% of 25mm mineral aggregate, 70.0% of recycled aggregate, 1.89% of filler and 0.315% of recycling agent by weight. Test section was constructed on national highway #38 and opened on September 2015. Field performance such as crack, rutting and roughness was measured by means of automated pavement evaluation vehicle for three times on July 2017, 2019 and 2021. Crack ratio of the test section increased up to 20.45% for six years since it opened in 2015. More crack was developed on the second lane than the first lane due to the higher heavy vehicle ratio on the second lane. The difference of crack ratio between the reclaimed asphalt pavement and the mineral aggregate asphalt pavement was less than 2% for six years. More rut depth was developed on the mineral aggregate asphalt pavement than the reclaimed asphalt pavement and the statistical significance was verified by t-test. Longitudinal roughness was increased more on the mineral aggregate asphalt pavement than on the reclaimed asphalt pavement and the statistical significance was also verified by t-test. From the field test for six years, it is concluded that the field performance of reclaimed asphalt pavement was not reduced by using the recycled aggregate and the service life of reclaimed asphalt pavement showed no difference comparing to the mineral aggregate asphalt pavement.

배수성 아스팔트 포장 분석을 통한 도시 열섬 현상 저감에 관한 연구

송현호,장대성,이재준 한국도로학회 2020 한국도로학회논문집 Vol.22 No.6

PURPOSES : This study aims to reduce the urban heat island phenomenon via utilization of porous asphalt pavements. METHODS : One of the many known functions of porous asphalt is that it reduces the urban heat island phenomenon. Indoor experiments were conducted to compare the surface temperature of sprinkled dense-graded and porous asphalt and outdoor experiments were conducted to verify the difference between the two asphalt pavements under external conditions. RESULTS : The results of the indoor experiment demonstrated that the temperatures of the two pavements were similar and that the porous asphalt pavement exhibited low temperature when sprinkled; the temperature of the porous asphalt was approximately 2 °C lower than that of the dense-graded asphalt pavement. The results of the outdoor experiment showed that the peak temperatures of the two pavements were approximately the same as usual. However, it was confirmed that the surface temperature of the porous asphalt pavement at night after sunset was lower than that of the dense-graded asphalt pavement and that the peak temperature dropped for approximately 1~2 days after the rainfall.. CONCLUSIONS : Porous asphalt pavement has a lower surface temperature than normal dense-graded asphalt pavement, under the presence of moisture in the pavement. In addition, it was confirmed that the lower surface temperature of the porous asphalt pavement is due to the low heat emission of the pavement at night. Accordingly, it is believed that the application of the porous asphalt pavement will not only have known effects but also significant impacts on the reduction of urban heat island phenomena.

예방적 유지보수를 위한 초박층 아스팔트 포장의 성능 평가

김부일 한국도로학회 2020 한국도로학회논문집 Vol.22 No.2

PURPOSES : The purpose of this study is to evaluate the performance of an ultra-thin asphalt pavement as a preventive maintenance approach through laboratory tests. METHODS : An ultra-thin asphalt pavement of 2 cm wearing course thickness comprising modified asphalt and aggregate is a preventive maintenance method used for asphalt pavements. A mix design was carried out to determine the optimum aggregate gradation and asphalt contents. A dynamic immersion test was performed to evaluate the water-resistance of the ultra-thin asphalt pavement. A wet track abrasion test and a cohesion test were conducted to examine the applicability of the ultra-thin asphalt pavement in surface treatment. The performance of the ultra-thin asphalt pavement was evaluated through wheel loading tests, such as Hamburg wheel-tracking and third-scale model mobileloading simulator (MMLS-3). RESULTS : An optimum binder content of 4.9% was obtained in the ultra-thin asphalt mixture from the Marshall mix design. The waterresistance tests indicated a 70% dynamic immersion coverage rate of the ultra-thin asphalt pavement. The wet track abrasion test showed an abrasion rate of 0.0107 g/cm2, and the cohesion tests indicated a 19.0 kg·cm average cohesion at 30 min of operating time and 21.4 kg·cm average cohesion at 60 min of operating time. From the Hamburg wheel-tracking test, a 16.56 mm rut depth at 20,000 wheel passing was obtained. Finally, a 5.87 mm rut depth at 300,000 number of wheel passing was detected from the MMLS-3 test. CONCLUSIONS : The water-resistance of the ultra-thin asphalt pavement satisfied the recommended guidelines of the Korean Ministry of Land, Infrastructure and Transport. In addition, the applicability of the ultra-thin asphalt pavement as a surface treatment met the standard of the International Slurry Surfacing Association. Furthermore, the deformation performance of the ultra-thin asphalt pavement was 1.5 times better than that of the straight asphalt pavement, based on the results of the wheel-loading tests. Hence, it is estimated that an ultra-thin asphalt pavement has a high performance in the preventive maintenance of asphalt pavement, even though the cracking resistance was not evaluated in this study.

Properties of Emulsified Cation Latex in Asphalt Pavement

Hyoung Seok Han,Sang Jin Na,Hyung Min Lee,Jeong geun Kim 한국도로학회 2018 한국도로학회 학술대회 발표논문 초록집 Vol.2018 No.05

In the United States and Europe, new environmentally friendly asphalt pavement has been researched as an alternative to traditional hot asphalt pavement. After the Paris Convention of 2015, policies should be found to reduce carbon dioxide. In the field of asphalt pavement, new methods are needed to reduce carbon dioxide from the traditional hot asphalt pavement. In Korea, waste asphalt is growing and natural aggregate is running dry. So the government is implementing policies to increase the use of waste resources. So, it created a new asphalt pavement method to reduce CO2 and use waste asphalt. It is a cold recycled asphalt pavement. Emulsified asphalt has a balance of dispersibility, stability, and adhesive between water, aggregates, and asphalt. But, the physical properties of emulsified asphalt can be degraded compared to traditional hot asphalt pavement. So there are limitations in actual use. The study compared the softening point, elastic recovery, and penetration properties of asphalt mix compounds by using latex in emulsified asphalt. In particular, cations latex was used for the emulsified asphalt, which could further improve the physical properties.

포장가속시험을 이용한 보수형 배수성포장의 온도저감 효과 및 소성변형 저항특성 연구

곽병석,서영찬,송철영,김주원 한국도로학회 2009 한국도로학회논문집 Vol.11 No.3

높은 포장온도는 아스팔트포장 소성변형의 주요인이나 소성변형을 줄이기 위한 방안으로서 포장온도를 줄이는 측면에서는 아직 많은 연구가 이루어지지 않은 실정이다. 본 연구에서는 소성변형결함을 줄이기 위한 하나의 대안으로, 온도저감 효과가 있는 것으로 알려져 있는 보수성 포장을 배수성포장의 하부층에 설치한 포장의 공용특성을 연구하였다. 본 연구의 목적은 보수형 배수성 포장의 온도저감효과를 정량화하고, 포장가속시험(Accelerated Pavement Testing)을 이용하여 온도저감에 따른 소성변형 감소효과를 확인하고, 정량화하는데 있다. 또한 추가적으로 보수성 포장의 상대강도계수를 분석하고, 일반 포장과 비교하여 설계법 적용시 포장두께를 줄일 수 있는지 여부를 알아보고자 하였다. 본 연구를 위해 보수형 배수성포장 2개 단면 및 일반 배수성포장 1개 단면 등 총 3개 시험구간이 시공되었다. 히팅 및 살수를 일정주기로 실시하였으며 하중조건은 윤하중 8.2ton, 타이어 공기압 7.03kgf/cm2 타이어 접지면적 610cm²이었다. 이 연구에서 포장체 온도저감효과는 중간층의 경우 6.6∼7.9℃(평균 7.4℃), 표층의 경우 7.9∼9.8℃(평균 8.8℃)였으며, 이를 통해 포장표면의 소성변형 발생을 26% 감소시킬 수 있었다. 또한 탄성계수로부터 추정된 보수성 포장의 상대강도계수는 0.173으로 일반 밀입도 포장의 1.2배정도였으며, 일반배수성 포장 구간에서는 표층, 중간층, 기층 모두 소성변형이 발생한데 반해 보수형 배수성포장 구간에서는 표층에서 대부분의 소성변형이 발생된 것으로 나타났다. One of the main causes of asphalt rutting is high temperature of the pavement. Nevertheless, there has been few research on lowering the pavement temperature for reducing rutting. This study investigated the performance characteristics of moisture-retaining porous asphalt pavement, which is known to have a temperature reducing effect. The purpose of this study is to quantify the temperature reducing effect of moisture-retaining porous asphalt pavement and its effect of reducing rutting through Accelerated Pavement Testing(APT). Additionally, the possibility of reducing the thickness of the pavement in comparison to general dense grade pavement by analyzing structural layer coefficient of moisture retaining pavement. A total of three test sections consisting of two moisture-retaining porous asphalt pavement sections and one general dense-grade porous asphalt pavement section were constructed for this study. Heating and spraying of water were carried out in a regular cycle. The loading condition was 8.2 ton of wheel load, the tire pressure of 7.03kgf/cm2, and the contact area of 610cm². The result of this experiment revealed that the temperature reducing effect of the pavement was about 6.6∼7.9℃(average of 7.4℃) for the middle layer and 7.9∼9.8℃ (average of 8.8℃) for surface course, resulting in a rutting reduction of 26% at the pavement surface. Additionally, the structural layer coefficient of moisture retaining pavement measured from a laboratory test was 0.173, about 1.2 times that of general dense grade pavement. The general dense-grade porous asphalt pavement test section exhibited rutting at all layers of surface course, middle layer, and base layer, while the test sections of moisture-retaining porous asphalt pavement manifested rutting mostly at surface course only.

섬유 그리드를 이용한 아스팔트 포장 단면 감소 효과 분석

함상민,김부일 한국도로학회 2017 한국도로학회논문집 Vol.19 No.5

PURPOSES : The purpose of this study is to verify the effects of fiber grid reinforcement on the thickness reduction of asphalt pavement. Test sections were constructed on the national highway to evaluate the structural capacity of asphalt pavement with the reinforced fiber grid and normal asphalt pavement. METHODS: Falling Weight Deflectometer (FWD) tests were performed to measure the structural capacity of test sections. The loads of the FWD test are 4.1 ton, 8.0 ton, 10.0 ton, and loaded twice, respectively. The test sections consist of a reference asphalt pavement section, an asphalt pavement section reduced with a 5-cm base layer thickness, and a fiber grid reinforced asphalt pavement section reduced with a 5-cm base layer thickness. In addition, strain data was collected using strain gauges installed in the test sections. RESULTS: The results of the FWD tests showed that the deflections of the pavement section reinforced with the fiber grid was reduced by about 14% compared with that of the reference asphalt pavement section. The strain at the bottom of the asphalt surface layer of the pavement section reduced to a 5-cm base thickness and reinforced with a fiber grid was similar to that at the bottom of the asphalt layer of the reference asphalt pavement. CONCLUSIONS : The results of the FWD and strain tests showed the possibility of the pavement thickness reduction by reinforcement with a fiber grid.