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
제25권 제3호 (2023년 6월) 12건
1.
2023.06
구독 인증기관 무료, 개인회원 유료
PURPOSES : During the summer of 2018, a heat wave (temperatures > 33°C) lasted for more than 30 days, causing blow-ups at eight different locations in South Korea. The blow-up phenomenon occurred when the internal temperature of the concrete slab increased. Simultaneously, as the concrete slab expands excessively, the length of the end of the slab increases, thus resulting in a lateral compressive force; when the slab cannot withstand this force, it rises or breaks. Blow-up is caused by a variety of factors, including increased temperature and humidity, accumulation of incompressible substances inside discontinuous surfaces, alkali–silica reactions, and aging of the concrete pavement. Several researchers have presented models to forecast blow-ups, such as the A. D. Kerr and G. Yang models, which have been applied to explain the blow-up phenomenon. However, this model has some limitations. This paper discusses a method to overcome these limitations.
METHODS : Buckling, the most important theory describing the blow-up phenomenon, was reviewed, and the buckling principle was confirmed. Subsequently, the input variables of the Kerr and Yang models and the mechanism for predicting the occurrence of blow-ups were identified. The PGBA program was used to confirm the lifetime of the expansion joint and the blow-up occurrence time based on the expansion joint spacing to review the limitations of the two studied models.
RESULTS : The Kerr and Yang models did not consider variables such as the expansion joint spacing or length of the integrated adjacent slab. In other words, it is necessary to reconsider the appropriateness of blow-up time predictions in relation to changes in expansion joint spacing and slab length. The expansion joint lifetime and blow-up occurrence time were predicted using the PGBA program. It was confirmed that as the expansion joint spacing increases, the expansion joint lifetime decreases. However, the blow-up occurrence time was shown to be the same (equal to 59 years), which is a limitation of the Kerr and Yang models used in the PGBA program. This resulted in a limitation in which variables for the expansion joint spacing cannot be used.
CONCLUSIONS : Through blow-up simulation experiments and actual field data, an appropriate slab length should be determined, and a blow-up model should be developed based on the slab length. If a blow-up prediction based on concrete slab length and a blow-up model based on are developed, the blow-up prevention technology will be applied to the appropriate blow-up time and location to avoid traffic accidents and reduce human and property damage.
4,500원
2.
2023.06
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study was conducted to compare and evaluate the compaction performance and physical properties of recycled asphalt mixtures by utilizing the characteristics of hot-mix asphalt mixtures and foamed asphalt.
METHODS : A wearing-course mixture was used for performance evaluations. Subsequently, dynamic shear rheometry (DSR), compaction performance, general physical properties, tensile strength ratio, and Hamburg wheel tracking were tested.
RESULTS : As a result of performance comparisons, compaction, and general physical properties satisfied the quality standards. In the Hamburg wheel tracking test, the mixture with the antistripping agent improved performance by approximately 40% compared with the general mixture. As the foamed asphalt binder was produced at a relatively low temperature compared with the general hot-mix asphalt binder, the penetration, viscosity, and DSR test results of the aged foamed asphalt binder showed that the aging of the asphalt binder was suppressed, and the flexibility increased. Therefore, the resistance to fatigue cracks is expected to be enhanced.
CONCLUSIONS : Even though the foamed warm-mix recycled asphalt mixture was produced at a temperature that was 20~30°C lower than the hot-mix asphalt mixture, its physical properties were similar to those of the hot-mix asphalt mixture; its use is expected to reduce the production of fuel and air pollutants.
4,000원
3.
2023.06
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study predicts the concentration of suspended road dust (PM10) by analyzing meteorological, traffic, and atmospheric environmental data acquired at various angles, and attains a comprehensive understanding of the influencing factors of suspended road dust.
METHODS : Experimental field methods were applied and statistical analyses were conducted. Field experiments were conducted using a vehicle-based measurement of suspended dust (PM10) to measure its concentration at the measurement site while maintaining a constant driving vehicular speed. Statistical analysis demonstrated the effects of the concentration of suspended dust on changes in meteorological and environmental factors and lanes per traffic volume at the time of measurement. Finally, a multiple linear regression model was applied to identify the factors which affected the generation of suspended dust.
RESULTS : The analysis of suspended road dust concentrations according to the lanes per traffic volume and environmental factors showed that suspended dust concentrations increased at increasing driving speeds. In addition, the background concentration at the monitoring station was higher at high-wind speeds (>3.0 m/s) than at low-wind speeds (<1.6 m/s), but the suspended dust concentrations were higher at low-wind speeds. During the temperature inversion period from evening to morning, the suspended effects of traffic and meteorological factors were greater than the background concentration at the station. Multiple linear regression analysis showed that excluding yellow-dust days, which are known to affect atmospheric pollution levels, the accuracy of the model improved and resulted in increases in background PM10, vapor pressure, sea-level pressure, visibility, after-rainfall time, and in decreases in insolation and precipitation during low-wind speed conditions.
CONCLUSIONS : At low-wind speeds, 5 days after rain, and when the relative humidity was higher than 72%, suspended dust was found to be higher than atmospheric PM10 concentration and may increase at increasing driving speeds and section lane traffic volumes. However, the volume of measured data in this study is limited to determining the patterns of suspended dust, as the silt loading of the operational road or the effects of prominent variables were not considered in this study. However, we identified prominent factors related to road-suspended dust for real-time road-dust predictions.
4,200원
4.
2023.06
구독 인증기관 무료, 개인회원 유료
PURPOSES : The purpose of this study was to improve the performance of concrete pavements by measuring the unit-water content with an Internet-of-Things (IoT)-based unit-water content measurement device at an increased precision compared with that of existing measuring equipment.
METHODS : We calculated the properties of concrete that varied according to variations in the unit-water content. To confirm the change in the performance of concrete pavements, we compared and analyzed the fatigue cracking rate and international roughness index of concrete pavements at the 20-year point of public use according to the changes in properties using the Korea Pavement Research Program(KPRP).
RESULTS : We confirmed that IoT-based measurement equipment can improve the performance of pavements without changing their mixing designs or specifications. We confirmed that the performance of the concrete pavements changed significantly, even with unit-water content variations within the range of quality standards. According to IoT-based unit-water content management, we confirmed that the performance of the concrete pavement (fatigue cracking rate and international roughness index) improved without changing the mixing design.
CONCLUSIONS : We confirmed that by using IoT-based unit-water content management, pavement performance can be improved. It is necessary to consider whether the application of this concept to other concrete property management items, such as the chloride content, is possible. Considering the changes in concrete properties according to the unit-water content based on laboratory tests and considerations of various load conditions will be necessary for future research.
4,000원
5.
2023.06
구독 인증기관 무료, 개인회원 유료
PURPOSES : The process of extracting and recovering an asphalt binder from an asphalt mixture is harmful to the human body and can affect the properties of the asphalt binder owing to the presence of residual solvent quantities. This study was conducted to determine the properties of aged asphalt binders based on rejuvenator content without extracting and recovering the asphalt binders using RAP mortar.
METHODS : After extracting and recovering aged binders from waste asphalt, a rejuvenator was added at a certain rate to evaluate the physical and rheological properties of the binder based on the added amount.
RESULTS : When the rejuvenator content was greater than necessary, the absolute viscosity was not properly measured owing to the behavior of the rejuvenator. The phase angle was measured to be almost 90°, thus indicating that it acted as a liquid . In addition, the shear strain and nonrecovery compliance also increased significantly.
CONCLUSIONS : If an excess rejuvenator quantity was added to the aged binder, the absolute viscosity was not properly measured, the phase angle was measured to be almost 90°, and the shear strain increased significantly. It is also necessary to conduct the same tests on different types of RAPs to ensure that the results of this study are reasonable.
4,000원
6.
2023.06
구독 인증기관 무료, 개인회원 유료
PURPOSES : The purpose of this study is to experimentally analyze the flexural strength characteristics of cement mortar mixtures simultaneously incorporated with graphene oxide (GO) and polyvinyl alcohol (PVA) fibers, and to understand the composite effect of those on enhancing resistance against the initiation and progression of micro-cracks, as well as the control of macro-cracks in flexural behavior.
METHODS : Cement mortar(w/c=0.5) specimens for flexural strength test, mixing 6 mm and 12 mm PVA fibers at 1% and 2% volume ratios, were fabricated. Additionally, specimens incorporating GO at a cement weight ratio of 0.05% were prepared for each mixture to analyze the effect of GO. Therefore total eight types of mixture were prepared. The fabricated specimens were subjected to flexural strength tests after curing in waterbath for 7 and 28 days. Concurrently, digital images for analyzing deformation in accordance with loading history were obtained at a rate of 20 Hz using the DIC technique. Through displacement and strain calculation via DIC, the flexural behavior characteristics of the mixtures combined with GO and PVA fibers were precisely analyzed. Furthermore, the composite effect on flexural behavior characteristics when GO and PVA fibers are incorporated was discussed.
RESULTS : For the PVA fiber-reinforced cement mortar mixture, the incorporation of 0.05% GO increased the crack initiation load by up to 23%, and the maximum resistive load after cracking by up to 24%. Moreover, introducing GO into the PVA fiber-reinforced mixture increased the flexural strain just before cracking by approximately 30 to 50%, while the maximum resistive load after cracking exhibited similar strain levels with or without GO incorporation. Therefore, under flexural behavior, the integration of GO might delay crack initiation by increasing the strain concurrent with the rise in flexural stress before crack occurrence. It also seems to contribute to reducing crack expansion by synergistically interacting with PVA fibers after crack occurrence.
CONCLUSIONS : It was experimentally examined that the flexural strength of PVA fiber reinforced cement mortar is improved by incorporating GO. Moreover, GO enhances resistance of crack occurrance and reduces crack propagation in combination with PVA fibers. This study suggests that simultaneous incorporation of GO and PVA fibers can synergistically improve the performance of cement composites.
4,000원
7.
2023.06
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study aims to conduct a sensitivity analysis to determine the major factors affecting traffic accidents involving elderly pedestrians.
METHODS : In this study, a regression tree model was built based on a non-parametric statistical model using data on traffic accidents involving elderly pedestrians. Using this model, we analyzed the degree of change in the probability of pedestrian fatalities.
RESULTS : Results of the model analysis show that the first major factor combination affecting traffic accidents involving elderly pedestrians is speeding, night time, and road markers. The second combination is night time and arterial roads (national and local highways). The last combination that may lead to such accidents is heavy vehicles and federally funded local highways.
CONCLUSIONS : Preventive measures, such as speed control, proper lighting, median strips, designation of pedestrian protection zones, and guidance of detours, are necessary to manage high-risk combinations causing accidents of the elderly.
4,200원
8.
2023.06
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study aims to evaluate the traffic safety by collecting and analyzing vehicle speed and conflict frequency data based on the provision of information to vehicle drivers and crosswalk pedestrians under right-turn conditions.
METHODS : Two evaluation scales, namely speed of access and number of conflicts, were used to quantitatively evaluate the effects of the new information provision method. Data on access speed and the number of conflicts according to information provision were collected and compared before and after information provision.
RESULTS : Analysis of the pre- and post-spot speed reduction rates revealed an overall reduction rate of 32.6%. The conflict ratio was 81.0% before information provision but increased to 83.3% after information provision.
CONCLUSIONS : When LED display information was provided, the effect of decelerating the approaching speed of vehicles in the rightturn torpedo section was statistically significant, but the reduction in the conflict ratio was not. Factors such as intersection status, traffic volume and vehicle speed, affect the approach speed and increase or decrease the number of conflicts. Regardless of whether information is provided, the average compliance rate of the Road Traffic Act when turning right in the channelization area is 16.7%, which is significantly different from the average compliance rate of 48.4% immediately after the Road Traffic Act was revised in July 2022.
4,000원
9.
2023.06
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study proposes a method for comparative analysis, based on geographic information systems (GIS), that can be used when introducing demand-responsive transit in areas where public transportation is not available.
METHODS : To analyze areas where public transportation is neglected, bus stop location information, building location information, and administrative district boundary data for the census were acquired. Geocoding was used for address-based raw data to create a spatial database. Based on the collected data, the proportion of households separated by a certain minimum distance from a bus stop was aggregated and constructed through near analysis. When introducing a demand-responsive transit system, the operational cost was calculated and compared with the existing city bus transportation cost.
RESULTS : Results show that the operating costs of introducing demand-responsive transit can be compared and analyzed using the proposed method, for a case study of Daejeon Metropolitan City.
CONCLUSIONS : It is economically efficient to avoid the entry of route buses and introduce demand-responsive transit in areas isolated from public transportation where the number of people getting on and off is extremely low.
4,000원
10.
2023.06
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study aims to suggest how to utilize "standby data" of shared mobility that does not contain personal information and examine whether "standby data" can derive existing shared mobility operation analysis items similarly.
METHODS : An existing Personal Mobility (PM) traffic pattern analysis was performed by identifying the user (User ID) and the user's route in a time frame. In this study, the PM traffic pattern analysis focuses on a vehicle (ID of the standby vehicle) and its standby location. We examined whether the items derived from the User ID-based traffic pattern analysis could also be derived from the standby Vehicle ID-based analysis.
RESULTS : The analysis showed that all five items (traffic volume by time slot, peak time, average travel time, average travel distance, and average travel speed) of the existing User ID-based PM travel analysis result could be derived similarly using the standby Vehicle ID-based PM traffic analysis. However, the disadvantage is that the average driving distance is calculated as a straight-line distance. It seems possible to overcome this limitation by correcting the average driving distance through linkage analysis with road network data. However, it is not possible to derive the instantaneous maximum speed or acceleration/deceleration.
CONCLUSIONS : In an era in which various means of transportation are being introduced, data sharing is not preferred because of legal issues.Consequently, it is difficult to understand the use of new means of transportation and formulate new policies. To address this, data sharing can be active based on standby data that is not related to personal information.
4,000원
11.
2023.06
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study aims to analyze the impact of demand risk on two public-private partnership (PPP) projects, namely BTO and BTO-a. The main aspects covered in this study are: i) identification of key risk issues considering the structure of PPP projects, and ii) game theory-oriented scenario building and simulation of demand risk allocation from participants’ perspectives.
METHODS : Using the institutional analysis and development (hereafter IAD) framework, a hypothetical structure is formulated to examine the interactions of demand risk. It develops a series of demand risk allocation models for PPP projects (i.e., BTO and BTO-a). The risk structures from the IAD step are the demand risk allocation issues. Using game theory-oriented simulation, this study evaluates demand risk based on scenario building.
RESULTS : First, this study highlights the imbalanced rate problems of returns between the BTO and BTO-a projects proposed by the market. This may lead to improvement measures geared towards problematic methods for determining the rate of return among domestic PPP projects. Second, compared with the BTO type, this study expects that the BTO-a type may exhibit more effectiveness, which can increase the probability of project success in both the public and private sectors. Third, judging from game-theory-oriented approaches, this study confirms the function of the BTO-a as a method to adjust moral hazard in the private sector.
CONCLUSIONS : Government management standards for BTO-a projects were derived based on the simulation results. It is necessary to select an appropriate project method based on rationality by balancing the IRR for each project method. Legal regulations should be applied separately to each part of the government guarantee. In addition, this study emphasizes that the introduction of ex-post value-for-money (VFM) analysis is essential for the efficient management of government expenses.
4,800원
12.
2023.06
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study aims to analyze the efficiency of the safety and management of private highways.
METHODS : Variables were selected based on the data and performance related to the safety of 18 private highways. The appropriateness of operations management was reviewed using Data Envelopment Analysis (DEA) analysis. Items with a scope for improvement were reviewed and adjustment measures were presented.
RESULTS : To increase safety management efficiency, the degree of reduction in personnel and operating expenses was presented based on the relative efficiency group.
CONCLUSIONS : It is necessary to adjust the appropriate management organization and operating costs according to the characteristics of each route. Moreover, the limitations of the study and possible improvements were presented.
4,000원
