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
제21권 제2호 (2019년 4월) 9건
도로 포장 및 시설
1.
2019.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : The purpose of this paper is to develop an evaluation method for aged reclaimed asphalt pavements using RAP mortar specimen and FTIR method.
METHODS: To evaluate the low-temperature behavior of aged reclaimed asphalt pavements, an indirect tensile strength test was adopted with an RAP mortar specimen. The RAP mortar specimen without a rejuvenator was fabricated with two fine aggregate types as a function of passing sieve sizes. The fabricated RAP mortar specimen was frozen for 24 h at -20℃. The indirect tensile strength was measured as a function of different absolute viscosities. The indirect tensile strength and displacement were varied as functions of the dosage of the rejuvenator. The spectroscopy analysis of four asphalt binders was performed under attenuated total reflection. The four asphalt binders comprised of a virgin binder, two extracted RAP binders, and a mixed virgin and extracted RAP binder. To evaluate the oxidation of the binder, the carbonyl index was calculated.
RESULTS : The four extracted RAP binders were measured with an extremely wide range of absolute viscosity from 30,000 poise to 170,000 poise. The indirect tensile strength of the RAP mortar decreased as the absolute viscosity increased. This means that at lower temperatures, the indirect tensile strength can indicate the oxidation of RAP. Also, the indirect tensile strength and displacement changed sensitively as the dosage of the rejuvenator was changed. Based on the FTIR principle, a good relation was observed between the dosage of the rejuvenator and the FTIR absorbance peak. It can be used to estimate the dosage of the rejuvenator in hot reclaimed asphalt mixture. Also, the carbonyl index of the RAP binder was calculated to evaluate asphalt oxidation using the FTIR principle.
CONCLUSIONS : There is a good relation between the indirect tensile strength of RAP mortar and its absolute viscosity. This indicates that RAP mortar can be used to estimate the properties of aged RAP. Also, the usage of rejuvenator can be evaluated with both the indirect tensile strength and FTIR absorbance peak. The carbonyl index can be used to predict asphalt oxidation.
4,000원
2.
2019.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : Recently, there has been an increase in the use of discrete randomly distributed fiber materials for reinforcing pavement foundations. However, very limited study has been made on this from the perspective of pavement engineering. Therefore, this study evaluates the performance of soil-geofibers used in pavement foundations as well as the effects of stress dependency with various mixtures.
METHODS: To estimate the behavior of soil-geofiber mixtures under traffic loadings, laboratory resilient modulus data for the mechanical characteristics of geofiber mixtures were used, and they were adopted to evaluate the structural response and analyze the stress dependency through 2-D finite element analysis. As the host materials, poorly graded and uniformly graded sand were selected, and each soil was mixed with three different types of fiber, namely monofilament, fibrillated, and tape.
RESULTS: The stress dependent response on resilient modulus and Poisson’s ratio were mainly considered by conducting linear and nonlinear elastic analyses on various geofiber mixtures. As a result, it was found that the response and yield function of geofiber mixed layers in pavements were affected considerably depending on the gradation of the soils and the confinement conditions. A small change was found when the particle size was homogenized.
CONCLUSIONS : From this, it can be concluded that the finite element model with stress dependency is suitable for estimating the performance on geofiber mixtures. It is also noted that all the responses of geofiber mixtures were relatively sensitive to the gradation of host soils. This indicates that the effects of the nonlinearity and stress-dependency of geofiber mixtures under repetitive loadings could be substantial.
4,000원
3.
2019.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : In Korea, asphalt overlay has been used as a typical alternative rehabilitation method for deteriorated pavements. However, asphalt overlay has problems due to poor bonding of the asphalt overlay and the old concrete. Recently, concrete overlays, which have advantages such as long-term durability and high structural capacity to carry heavy traffic, have been considered for rehabilitation construction. However, concrete overlays have limitations such as difficulty in opening to traffic and pavement noise. Recently, an appropriate fine-size exposed aggregate concrete pavement technique was reported to solve these problems. Therefore, this study aims to suggest an optimum mixture design of fine-size exposed aggregate concrete overlay (EACO) that can ensure low noise and early strength.
METHODS : The optimum mixture design of fine-size EACO is determined to ensure adequate structural performance for early traffic opening and good functional performances such as low noise. Therefore, the optimum mixture proportion is determined based on the optimum design of aggregate content to produce a low-noise pavement texture by controlling the exposed aggregate number (EAN) and mean texture depth (MTD).
RESULTS : The water-cement ratio and unit cement ratio were used to determine the mixture designs to achieve workability and adequate strength for early traffic opening. The texture was determined by selecting the maximum size of coarse aggregate smaller than 10 mm with an S/a ratio of less than 30% for low noise. With these mixture proportions, the EAN and MTD were 50±5 / 25cm2 and 1.0±0.2 mm. Respectively, which meet the criteria for EACO.
CONCLUSIONS: In this study, an optimum mixture design of EACO for early traffic opening and low noise is suggested by using earlyhigh strength cement, and the pavement texture is implemented considering EAN and MTD. In addition, a pavement surface texture criterion is suggested for the quality control of EACO.
4,300원
4.
2019.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : The purpose of this study is to evaluate the performance of road stone block pavements using APT (Accelerated Pavement Testing), which can evaluate the short-term pavement performance of a pavement structure for a given traffic load.
METHODS : The performance of stone block, concrete block, and asphalt (modified SMA) pavements were evaluated according to the cumulative equivalent load by using APT. The FWD (Falling Weight Deflectometer) test was used to analyze the deflection per unit load. In addition, the plastic settlement was analyzed by transverse profile measurement.
RESULTS: The results of the APT of about 197,000 ESALs (Equivalent Single Axle Loads) show that there were no damages in the stone block, concrete block, and asphalt pavement, such as breakage of stone or concrete block, cracking of asphalt, deflection, and plastic settlement of the wheel-pass section. It was analyzed that the bearing capacity of each pavement section did not decrease sharply with increase in cumulative ESAL. The results of plastic settlement analysis show that in the case of asphalt pavement, the plastic settlement steadily progressed from the beginning of the APT, and a settlement of about 4.76 mm occurred. In the case of concrete block and stone block pavements, no significant change occurred after the initial stabilization step, and plastic settlement of about 1.01 mm and 0.17 mm occurred for the concrete block and stone block pavements, respectively.
CONCLUSIONS : As a result of the analysis of the bearing capacity and plastic settlement after the APT, the performance of stone pavement was found to be similar to that of asphalt pavement and concrete block pavement. Therefore, it is concluded that stone pavements are applicable for the road pavement system.
4,000원
5.
2019.04
구독 인증기관 무료, 개인회원 유료
PURPOSES: This study was conducted to investigate the causes of damage and to suggest proper repair methods for the sections in which a number of transverse cracks and faulting occurred in JCP (Jointed Concrete Pavement) slabs during the early-age performance period.
METHODS: Field crack survey, FWD (Falling Weight Deflectometer) investigation, dowel bar installation condition survey, longitudinal profile survey, and in-situ core specimen inspection were conducted. .
RESULTS : As a result of the analysis, it was found that there was no decline in the composite modulus of the subgrade reaction (k-value). The dowel bars were properly installed, but the LTE (Load Transfer Efficiency) of the joint and transverse cracks were analyzed to be very low. In addition, it was found that there are voids in the bottom of the slab at the joints and corners. Due to the excessive built-in curling in the early age of concrete pavement construction, upward curling displacement occurred at the joints and corners, resulting in voids at the bottom of the slab. As a result, it was found that transverse cracks occurred due to the defective joint LTE.
CONCLUSIONS: Excessive built-in curling can cause early age cracks in the JCP slabs. In order to minimize the occurrence of reflection cracks after the application of the asphalt overlay in the future, concepts of alternative repair methods were proposed.
4,000원
6.
2019.04
구독 인증기관 무료, 개인회원 유료
PURPOSES : This study establishes a pay adjustment factor scheme that will penalize or provide incentives to contractors after pavement construction in Seoul City.
METHODS: Random sampling was conducted, wherein acceptable quality characteristics (AQCs) of the field mixture such as the aggregate gradation, asphalt binder content, pavement thickness, field air void, and IRI (International Roughness Index) were determined. Using the acquired field data, the percent within limit (PWL) values of each AQC were determined.
RESULTS : Weight factors were used to consider the effect of each AQC, since field data varies depending on the field condition. The total pay factor (PF) was determined by combining the PF material and PF construction. PF material considers the asphalt binder content and the aggregate gradation, while PF construction considers the field air void, pavement thickness, and field IRI.
CONCLUSIONS: A pay adjustment factor was established by determining the PWL of each AQC and calculating the corresponding pay factor. Based on the results, it is found that PWL is a reasonable and acceptable method for evaluating the pavement quality and determining the pay factor.
4,000원
7.
2019.04
구독 인증기관 무료, 개인회원 유료
PURPOSES: This paper presents the noise reduction effect of asphalt concrete pavement using steel slag aggregate.
METHODS: Steel slag aggregates induce various mechanical effects because of their high stiffness and specific gravity. It is also known that the noise reduction effect is due to its high specific gravity and porous nature. In this study, the noise reduction in a steel slag asphalt concrete pavement section was measured and analyzed.
RESULTS : On average, an asphalt concrete pavement with steel slag reduces road traffic noise by about 2 dB(A). In addition, the analysis of sound pressure levels by frequency showed lower sound pressure levels in steel slag asphalt concrete pavement than general HMA in all frequency ranges (from low to high frequencies). An analysis of the benefits with regard to noise, by assuming a road-traffic noise reduction of 2 dB(A) with asphalt concrete pavement using steel slag, shows that the noise abatement cost approach can save 1.6 million won a year over soundproof wall costs. In addition, the noise damage cost approach results in cost savings (with regard to noise) of between 19 and 60 million won per year depending on the population density.
CONCLUSIONS: The use of steel slag aggregate as an asphalt concrete mixture material not only improves the mechanical performance but also has a noise reduction effect. It is expected that the steel slag asphalt concrete pavement can reduce the environmental burden by utilizing resources and provide a safer and more comfortable pavement condition to the road users.
4,000원
도로교통체계
8.
2019.04
구독 인증기관 무료, 개인회원 유료
PURPOSES: This study analyzed the differences in drivers’behaviors and car movements between drowsy driving conditions and normal driving.
METHODS: This study analyzed behavior data from 32 participants and the related car movement data in a field test under drowsy driving and normal driving conditions. Acquired data were closed-eye time, distance between the test car and the left lane, distance between the test car and the right lane, driving speed, video clip of the driver’s face during driving, and so on. A total of 30 samples for drowsy driving and normal driving were selected once errors had been excluded.
RESULTS: There were three factors that differed between drowsy driving and normal driving conditions: closed-eye time, distance between the test car and the left lane, and distance between the test car and the right lane. These results were significant at the 0.05 level.
CONCLUSIONS : This study shows that there are three factors that vary significantly between drowsy driving and normal driving conditions that can be useful for detecting drowsy driving. Future studies should be designed with these results in mind, further considering, age, type of road, study site, and so on.
4,000원
9.
2019.04
구독 인증기관 무료, 개인회원 유료
PURPOSES: This study aims to contribute to a better road environment, which can result in accident reduction from two-wheeled vehicles, by analyzing factors affecting the two-wheeled vehicles’ accident severities in Incheon Metropolitan City.
METHODS: In this study, the two-wheeled vehicles’ accident severity was classified into four categories (fatal injury, serious injury, minor injury, and injury report) as a dependent variable, and 97 independent variables out of 14 categories were considered to construct an ordered probit model. To determine the factors affecting accident severity, the statistical package LIMDEP was used.
RESULTS: Among the variables used in the analysis, variables related to accident occurrence date (first quarter), region (8-district), accident type (passing the edge of the road of the vehicle for a pedestrian accident, fixed object collision, and overturn of vehicle-only accident), violation type (unobtained safety distance, failure to perform safe driving, violation of intersection driving, and violation of others), the type of road (at the intersection, near the intersection, at the crosswalk, near the crosswalk, etc.), gender of assailant (male), vehicle of victim (pedestrian and motorcycle), and age of victim (under 20) were found to have a statistically significant effect on the severity of the accident.
CONCLUSIONS: The variables related to accident type (fixed object collision and overturn of vehicle-only accident), gender of assailant (male), and vehicle of victim (pedestrian and motorcycle) have turned out increasing the accident severity. In addition, accident occurrence for two-wheeled vehicles is more diverse and vulnerable to damage than automobile accidents. Therefore, it is time to recognize the seriousness of two-wheeled vehicle accidents and to improve the environment and systems for safe driving.
4,000원
