간행물
한국도로학회논문집 KCI 등재 International journal of highway engineering
- 발행기관 한국도로학회
- 자료유형 학술지
- 간기 격월간
- ISSN 1738-7159 (Print)2287-3678 (Online)
- 수록기간 1999 ~ 2024
- 주제분류 공학 > 토목공학 공학 분류의 다른 간행물
- 십진분류KDC 534DDC 625
권호리스트/논문검색
제22권 제2호 (2020년 4월) 12건
1.
2020.04
구독 인증기관 무료, 개인회원 유료
Structural Evaluation of Subbase Layers at Different Test Sites using a Falling Weight Deflectometer
PURPOSES : The purpose of this study is to evaluate the structural effects of subbase materials and surface layer thickness obtained from different sites.
METHODS : Using a falling weight deflectometer, structural indexes such as SM(r), surface curvature index, base damage index, base curvature index, and AREA, were determined and compared with those of the control section. The back-elastic moduli for each layer were evaluated using the BALM program, and the tensile and compressive strains were analyzed using the KENLAYER program. The damage analysis was conducted to determine both the permanent deformation and fatigue cracking under repeated loading.
RESULTS : Increasing the surface layer can improve the elastic moduli of the construction section and compensate for the inclusion of different percent finer within 5% in the subbase layer.
CONCLUSIONS : The structural effect of adding 5% of 50 m/m aggregate can be compensated for by increasing the thickness of the surface layer.
4,000원
2.
2020.04
구독 인증기관 무료, 개인회원 유료
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.
4,000원
3.
2020.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : The purpose of this study is to estimate the reduction of traffic noise in a double-layered specific porous pavement based on the traffic speed variation.
METHODS : The close-proximity method was used in noise measurement, and the running speed was measured at 10 km/h and from 50 to 80 km/h.
RESULTS : From the quantitative analysis, it was found that the double-layered porous pavement reduced by 9.4 dB (A) on the average and 9.16 dB (A) at a 95% confidence level.
CONCLUSIONS : The use of porous pavements have been recommended to minimize traffic noise. In this study, it is quantitatively demonstrated that the double-layered porous pavement can reduce the traffic noise by more than 9.0 dB(A).
4,000원
4.
2020.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : Asphalt pavements are damaged by various causes, such as cracks, potholes due to climate, and traffic environment. Asphalt aging has a significant effect on cracks, which may also form potholes. The purposes of this study are to estimate the change in asphalt binder and mixture performance and to correlate the physicochemical changes of the asphalt binder and mixture performance with aging.
METHODS : The aging process of the asphalt was determined in the laboratory, based on the methods used in previous studies. In terms of consistency (stiffness), crack-resistance performance, moisture susceptibility, SK investigated the binder part, and Shoreki investigated the mixture part depending on the aging time.
RESULTS : The consistency (stiffness) and brittleness of both the asphalt binder and mixture tended to increase with aging. In particular, the crack-resistance performance of the asphalt binder (G*sinδ, ductility, and ΔTc) and mixture (flexural fatigue test and Cantabro test) deteriorated because of asphalt aging. Furthermore, the aging mechanisms (oxidation and polymerization) were identified based on the chemical structure analysis.
CONCLUSIONS : It is confirmed that the aging affected the chemical composition change and the physical properties of the asphalt. Asphalt pavements are significantly affected by the aging characteristics of the binder. It is concluded that the crack-resistance performance of the mixture decreases with aging due to these physical and chemical changes.
4,000원
5.
2020.04
구독 인증기관 무료, 개인회원 유료
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.
4,000원
6.
2020.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : The purpose of this fundamental study is to estimate the concentration of resuspended road dust in urban areas. This involves examining and measuring the factors that affect the dust concentration and measuring these factors and the concentration directly and indirectly by analyzing the factor-effect relationship of the dust in actual operation.
METHODS : From the literature review, the factors that influence resuspended road dust, including traffic, environment, and weather data of roads and their relationship analysis were obtained to determine the effects of each element on resuspended road dust. The data characteristics and the quantitative changes in the factors when a high concentration of resuspended road dust is generated are analyzed for each condition. The concentrations of the resuspended dust are presented from the perspective of each factor.
RESULTS : When the vehicle speed increased from 60 to 80 km/h, the measured resuspended dust concentration increased by 8㎍/m3 on the average. When the traffic was grouped, the resuspended concentration at 1200-1400 veh/h was 15.84㎍/m3 higher than that of 500-800 veh/h. A high concentration of 60㎍/m3 or more was generated in the SCL high and middle sections, and a high concentration of 10㎍/m3 or more was generated in the SCL low section. Eight cases were observed in the SCL high and middle section at an intense atmospheric wind speed of 3 m/s or more than the SCL level of zero cases. A high concentration of 89.8㎍/m3 resuspended dust was observed after 31 h of rainfall, and the dust concentration gradually decreased by over 50 h. Hence, the passing time after the rainfall, SCL and wind speed, traffic and vehicle speed, and air background (observation) concentration, all have a direct effect on the resuspended dust concentration. Atmospheric temperature and relative humidity have a significant effect on atmospheric dust concentration.
CONCLUSIONS : The quantitative indicators of the factors using an estimation model of resuspended road dust in urban areas can be obtained if the conditions for high concentrations of resuspended dust are established using the quantitative relationship of the resuspended road dust factors presented in this study.
4,200원
7.
2020.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : The adhesive bonding strength of the grid between asphalt pavements is critical in pavement performance. The study is to compare and evaluate the interlayered bonding strength of asphalt mixture specimens with fiber-glass grid (FG) reinforcement and different tack coating materials based on the test results of the shear bonding test.
METHODS : Asphalt mixtures were molded with FG reinforcement using various tack coating materials namely RSC4 and D/B coat. The adhesive shear-bond strength was measured by inducing a monotonic shear loadnig rate of 5 mm/min at 20℃.
RESULTS : As expected, the asphalt mixture with non-reinforced FG exhibited the highest adhesive shear-bond strength, followed by that of the FG with D/B coating. The ranking order of superiority is as follows: Control (RSC4) > D/B+FG > RSC4+FG.
CONCLUSIONS : The results of this experimental study indicate that FG with RSC4 and D/B tack coats can be successfully used in asphalt concrete overlay construction with superior field performance. Based on the test results and literature review, the field bonding strength should exceed 300kPa in grid reinforced asphalt pavement.
4,000원
8.
2020.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : In this study, a virtual driving simulator was used to analyze the effects of implementing appropriate highway driving criteria on the attentiveness of motorists on Korean highways.
METHODS : The study includes three scenarios. Scenario 1 was purposed to investigate the relationships between driver focus, the brain waves associated with drowsiness, and the speed of motorists driving along the straight 5-km section of Saemangeum South-North Road, which is the same as a car-only road. Scenarios 2 and 3 were designed to have shorter straight sections to enable comparison of the occurrence of drowsiness-related brain waves and velocity changes at 3 km and 2 km, respectively.
RESULTS : Driver focus was found to decrease and result in speeding after driving 2.5 km of the straight section. Past this point, driver focus continued to decrease, and drivers continued to accelerate. However, upon reaching a curved section, driver focus increased according to the linear change; furthermore, drivers showed a tendency to reduce their speed to a value near the speed limit.
CONCLUSIONS : According to the analysis of highway traffic accidents that occurred between 2013 and 2015, approximately 50% of total traffic accidents are due to speeding, drowsiness, and negligence. Therefore, if appropriately long straight sections, i.e., sections that are not associated with a reduced ability to focus, are calculated and implemented in road planning and operation, it is possible to prevent accidents caused by lack of driver focus.
4,000원
9.
2020.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : The purpose of this research was to present quantitative assessment items for each response phase, and to develop a virtual training method that police can use as a tool to effectively counter chemical terrorism in a crowded facility.
METHODS : In this study, domestic and foreign documents related to counterterrorism action and virtual training, as well as a police checklist for counterterrorism simulation, were examined.
RESULTS : A new checklist for counterterrorism drills was created; this checklist provides details regarding the tasks, trainees (team), execution, and accuracy at each phase based on the counterterrorism simulation checklist in Annex 4 of the Act on Safety Action at Facilities Vulnerable to Terrorism.
CONCLUSIONS : This study demonstrates the necessity of virtual counterterrorism training for police, and provides basic data that can be used for counterterrorism manual development/supplements, and virtual training system development.
4,000원
10.
2020.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : The purpose of this research was to select sites that are appropriate for the storage of individual protective gear that can be used by traffic-controlling police when chemical terrorism occurs.
METHODS : A storage facility, which is classified as Class A in the Act on Safety Action at Facilities Vulnerable to Terrorism, is defined for use in the event of soft-target chemical terrorism. Considering the number of controlled intersections and the police stations/substations within a radius of 750 m, the jurisdiction of traffic police and grade of protective gear were identified using ammonia, which has the widest protection boundary among known chemical terrorism substances.
RESULTS : The results indicate that mobilization should only occur after the police have put on protective gear at the nearby station, regardless of the police district. Additionally, Class B protective gear should be furnished if there is a police station/substation within the jurisdiction, whereas Class C protective gear should be furnished if there is police station/substation outside of the jurisdiction.
CONCLUSIONS : Because it is inefficient to keep protective gear at all police stations/substations, appropriate sites should be selected in accordance with chemical terrorism action strategy.
4,000원
11.
2020.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study was purposed to identify the relationships between route characteristics and accident characteristics using the data of 124 routes collected from 78 of the 136 Seoul Neighborhood bus companies.
METHODS : A structural equation modeling technique was employed for the analysis. The following four factors that were determined to influence the characteristics of Neighborhood bus accidents were implemented: driver characteristics, route characteristics, driver working conditions, and the management conditions of each company. Additionally, the two dependent variables were set as vehicle to vehicle accidents and vehicle to pedestrian accidents.
RESULTS : The results of factor analysis revealed that the management conditions of each company had a negative effect on the working conditions, and that driver characteristics had a negative influence on accident characteristics in the three models. The effects of three major factors such as route characteristics, management conditions of the company, and working conditions on vehicle-to-vehicle accidents were likely to be opposite to the influences on vehicle-to-pedestrian accidents.
CONCLUSIONS : Through the analysis of these results, we identified the characteristic causes of Neighborhood bus accidents. Specifically, a driver with more experience is less likely to be involved in a Neighborhood bus accident, and a narrower road is associated with higher accident risk. These results can be used as a reference to improve route and safety management for Neighborhood buses. Furthermore, this study is expected to contribute to the establishment of improved strategies to effectively reduce the number of Neighborhood bus accidents.
4,200원
12.
2020.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study was purposed to investigate whether the current passing sight distance standard is appropriate. Therefore, to determine a safe passing sight distance, data collected from the observations of a two-lane road were implemented in reliability analysis to develop a realistic passing sight distance model.
METHODS : First, passing sight distance data were collected for analysis from two-lane roads in Jeollabuk-do. Next, the speed profile was generated based on the collected data in order to analyze driver behavior. Finally, a model reflective of the driving behavior of motorists was developed and compared to the existing passing sight distance standard using reliability analysis.
RESULTS : As compared to the existing model for safe passing sight distance, the actual speed of the overtaking vehicle indicated higher acceleration and a longer acceleration duration. The entire model, with exception of the d1 section, was modified to reflect the overtaking behavior of motorists d1. d2 was set to correspond to the time until the vehicles run side by side (t21); Time t22 was set to correspond to the time until subsequent recovery to the main lane, and d3 was set to range between 19 and 47 m following review of the actual passing sight distance data. In addition, d4 was computed to be two-thirds of the distance d2, and the oncoming car was found to drive at a constant speed that was similar to the speed associated with d2 . Analysis of the reliability of the existing Korean passing sight distance standard revealed that the current standard does not recommend a safe passing sight distance for drivers.
CONCLUSIONS : As compared to the existing passing sight distance criterion, the actual speed and acceleration that driver apply to overtake a vehicle are higher, and the existing passing sight distance criterion is shorter than the actual passing sight distance. Additionally, the results of reliability analysis revealed that the proposed model developed to reflect driver overtaking behavior has more explanatory power than the existing one. Therefore, it is necessary to introduce new design standards that implement passing sight distance variables that are relevant to local drivers.
4,200원
