As a surface treatment method of concrete pavement in Korea, transverse tinning has initially been applied to improve drainage and friction at first. Since 2003, in order to reduce the noise of concrete pavement, longitudinal tinning have been studied and proved its superiority. Therefore, Korea Expressway Corporation (KEC) has applied this as surface texturing method in concrete pavement from 2008 to the present. However, the lateral vibration during vehicle running has been continuously raised in the longitudinal tinning section, and lots of efforts have been made to solve this problem. Nonetheless, complaints still occur intermittently in some sections. In this research, three sections in which complaints occur and three test sections were chosen to evaluate characteristics of lateral vibration between tire and longitudinal texturing. Based on the literature survey on the correlation between longitudinal texturing and tire, evaluation of the site and FEM analysis of each road surface were carried out. As a result of the analysis, the lateral vibration occurred most frequently in the random tinning section compared to other sections, and it was relatively few at the other improved tinning of the test section. Further studies on various tire types and timing intervals in the future will provide a standard of longitudinal texturing, which will reduce lateral vibration.

In Korea, a vehicle overtaking is prohibited by the law in tunnel and bridge sections where a road section has lanes with solid line. However, this regulation has some problems in terms of traffic operation and safety. So, it is necessary to find a way to improve the lane operation in tunnel and bridge sections. The objective of this research is to propose a systematical logic and specific standards to draw up an improvement of lane operation in tunnel and bridge sections on expressways. For that purpose, the status of lane operation in tunnel and bridge sections on both of the domestic and the abroad expressways and the improvement effect of the lane management were analyzed and, followed by it, the ways to improve lane management were suggested. In the comparison of the number of traffic accidents between road sections and tunnel sections, it was resulted that the number of traffic accidents per unit length (1km) of tunnel sections was lower than that of road sections. In addition, in the comparison of the fatality of traffic accidents, the fatality of tunnel sections on expressways was lower than that of other road tunnel sections. Through the analysis, it was resulted that there was a low correlation between the permission of the lane change in tunnel sections and the increase of traffic accidents. Moreover, in the comparing the traffic accidents between expressway tunnels and other road tunnels as well as between road sections and tunnel sections on expressways, there was no significant difference in safety between the solid line sections and the dotted sections. As a result of the analysis on the pilot operation section, it was expected that there would be no serious problems even if the permission of the lane change in tunnel and bridge sections was implemented, because the difference between in the existing solid-line sections and the pilot dotted line sections in terms of the lane change rate, the traffic characteristic, and the traffic accidents is not significant. Therefore, it needs to improve the current solid-line lane operation forbidding the lane change in tunnel and bridge sections. It is necessary to allow the lane change in tunnel and bridge sections with an appropriate level of facility conditions. In the long run, as in the cases of foreign countries, it is require to establish a principle to permit the lane change in tunnel and bridge sections. However, if necessary, it is need to consider the prohibition of the lane change in some tunnel sections by the engineering judgment. Allowing the lane change of the car in tunnel sections is not only merely a change of the lane operating method but also it is expected to be an important opportunity to increase the adherence of the driver to the laws and regulations and to change the drive culture by introducing a consistent traffic regulation.

Modified asphalt pavements are needed to resolve pavement distress problems like rutting, pot-hole and warm asphalt pavements are needed to solve energy saving, reduction of noxious gasses emission and early traffic opening. To present these two characteristics, we developed polymer-modified warm-mix asphalt binder and mixtures and evaluated their performance by optimizing polymer-modified warm-mix additive. As results, physical properties and rheological characteristics of polymer-modified warm-mix asphalt binder are similar to normal modified binder. And we confirmed that polymer-modified warm-mix asphalt mixtures satisfied quality standard of Ministry of Land, Infrastructure and Transport.

Recently, road cave-in and depression in urban area due to subsurface cavity are emerging as a social issue in Korea. These phenomena enable to cause not only damage to human lives and properties, but also an anxiety of the citizens. Furthermore, it is a problem that needs more fundamental solution to countermeasure. The objective of this study is to evaluate the stiffness characteristics of asphalt pavement with existence of subsurface cavity using Falling Weight Deflectometer (FWD) deflection and backcalculation analysis using GAPAVE program developed the KICT. The characteristics of FWD deflections are analysed for cavity and intact asphalt pavements. The stiffness reduction in the asphalt pavement due to subsurface cavity was evaluated as a result of this FWD test. The Seoul Metropolitan Government has conducted a Ground Penetrating Radar (GPR) test, coring, and image photographing in four different locations to determine the presence of the cavity and figure out the cavity depth and size underneath asphalt pavements. The cavity depths measured in this section range between 17cm to 51cm, and its lengths are at least 70cm to up to 310cm. It is found from this analysis that the deflections measured from cavity section are generally higher than intact section in same locations. As results of backcalculation analysis, it appears that the backcalculated moduli are generally decreasing with increase of cavity depth. After comparing with AC moduli obtained from intact and cavity section, it is observed that about 80% of moduli was reduced with existence of subsurface.

Recently, maintenance science has been promoted and many advanced equipments have been developed such as GPR surveying, automatic gauging robot, bridge deck inspection robot. And the government - led policy on the fourth industrial revolution affects the R & D field of science and technology, and science for all fields remains a challenge. However, the equipment that has been developed so far is applied separately to each field, so that it is not possible to grasp the state of the entire structure. Therefore, in this study, the applicability of BIM and image information mapping technology in expressway maintenance was analyzed. To accomplish this, a basic analysis was conducted to identify the characteristics of the equipment developed for the current structure inspection and to build a platform to manage the collected data collectively.

On the expressway, culvert structures serve as a channel or channel connecting villages and towns blocked by clay. The culvert structures are mainly constructed of reinforced concrete or corrugated steel sheets in various ground conditions. Most culverts are divided into aging and damage trends according to the number of public years. However, most of the damage to the culvert structures applied on the soft ground is likely to be caused by the subsidence of the ground. In addition, even if the settlement of the paper sheet is stabilized, if the road is constructed at the upper part, the culvert structure is also expanded at the time of the expansion work, and damage due to a behavior different from that before the expansion work may be found. Therefore, in this study, the behavior of the culvert structures according to the ground supporting force was analyzed. For this purpose, the causes of damage are derived through design review and field investigation.

Road construction and maintenance of deteriorated pavement has been continued since industrialization. Demand for aggregate with a good quality has been increasing from limited resources, but it is difficult to supply aggregates smoothly due to environmental protection regulations (Jo et al., 2015). Accordingly, efforts are being made in the road construction industry to utilize industrial products for the purpose of efficient use of resources and environmental preservation. Steel slag which contains a non-reactive CaO is used primarily as a material for embankment and soil covering depending on the expansion and environmental issues. On the other hand, steel slag shows a variety of performance improvements as including increased elasticity factors, increased indirect tensile strength, and improved plastic deformation resistance when handling the expansion issue with sufficient aging processing (Ali et al., 1991, Asi et al., 2007). In this study, the behavior characteristics of the slag asphalt concrete mixture were analyzed according to temperature to encourage the use of steel slag aggregate. Specimens with steel slag showed a higher initial strain than those with natural aggregates. But strain of specimens were nearly similar over the repeated temperature changes. The experimental results for specimens with these characteristics were less likely to cause the performance problems from temperature because the measured strains were relatively small than strain caused from other loads. In conclusion, it is necessary to design and construction process reflecting the behavior characteristics according to temperature to encourage the use of steel slag aggregate.

Korean government has been pushing the policy to lower the expensive toll on the private highways that has caused continuous complaints from the society because of relatively more expensive toll than that of the national highway which is managed by Korea Expressway Corporation(KEC). In Korea, seventeen private highways are under operation as of September, 2017. The average toll of the private highways is 1.51 times higher than that of the national highways. In the Ilsan-Toegyewon section(36.3 km) of the Seoul Outer Ring Highway which is composed of the northern private highway section and the southern national highway section, the toll discount was applied maximum 33% since March 29, 2018. With the application of this toll discount policy, the toll of Ilsan-Toegyewon section was lowered from 1.71 times to 1.1 times compared to that of southern national highway section in Seoul Outer Ring Highway. The applied business restructuring model to lower the toll on Ilsan-Toegyewon section this time is based on the combining the extension of operating period for another 20 years and the replacement of investors. It is reported that Korean government will continue to apply the business restructuring model to lower the toll on the private highways and promoting the benefit of public. If the KEC is participated in this type of business restructuring model as a new investor, the toll of private highway will be lower than the case of new private investor participating, due to lower borrowing rate of KEC.

As interest in automated vehicles increases, there is a need for automated vehicles and traffic management for them in transportation field is being raised, and related researches are being actively carried out. Traffic management for automated vehicles can be divided into longitudinal and lateral directions as in existing traffic management, but traffic management detailed strategies can be different for each direction. In this study, automated vehicles are applied to the variable speed limit, which is one of the longitudinal traffic management techniques, and the possibility of using automated vehicles in the variable speed limiting system is examined. Manual vehicles can receive traffic information by VMS, while V2X is used for automated vehicles. Therefore, various traffic information including speed limit information can be received from the road infrastructure ahead of manual vehicles. Simulation of how such a vehicle-infrastructure cooperation system can be utilized in a variable speed limit system is conducted and analyzed by market penetration rate (MPR) of automated vehicles. It is expected that the variable speed limit system of automated vehicles utilization, which is invetigated in this study, will be utilized for transportation management in the automated vehicles future.

This study examined the characteristics of research activities in the road sector via an analysis of patents and papers. For the text mining analysis, this study used keywords that contained the term “highway” and extracted data; 25,306 patents and 11,940 papers were used for the analysis. Along with a paper analysis, there is a 3P (paper, patent and patent) analysis method used to examine papers and patents. The 3P analysis method analyzes patent trends (time series, country, applicant, institution, and so on), original technology patents, the latest technology trends in the field of interest, and research trends by examining and evaluating key patent rights and their technology and utilization values. More specifically, analyzing patents owned by companies and papers published based on data obtained from text mining, allows researchers to compare intellectual property competitiveness by institution and identify a competitor’s research trends. Based on the results, commercialized tech areas and global research activity trends can be identified to establish a technology strategy. In this regard, this study used keywords only related to “highway” and acquired the following analysis results: To begin with, some of the most noteworthy research and development areas in the road and transport sector recently included “traction hybrid battery,” “information navigation date,” and “navigation determination.” This suggests great implications. Thus far, the road and transport section has traditionally researched “Construction of Roads, Railways, or Bridges” in Section E (Fixed Constructions) of the International Patent Classification and supporting works such as the installation of supports for the road or the construction of platforms, snow fences or similar arrangements. This study, however, found that lately, a lot of research is being conducted on systems such as transport control systems, transport safety, transport control radars or similar systems, sonar or Light Detection and ranging system, and anti-collision systems. In addition, as smart toll collection increasingly becomes available, a lot of research in the field of physics is being undertaken on transmission methods for measures, control signals or similar signs, and ticket dispensers or devices to collect tolls and admission fees. In conclusion, based on the above findings, this study was able to identify that more research in the road and transport sector is being conducted on smart toll collection and tech convergence such as physics and systems than traditional civil engineering as today’s world is heading towards the 4th Industrial Revolution.

Tensile stress occurs and random crack develops in concrete pavement slab when it contracts by variation of temperature and humidity. The tensile stress decreases and the random cracks are minimized by saw cutting the slab and inducing the crack with regular spacing. The sawn or formed joint depth must extend to between 1/4 and 1/3 of the pavement depth to ensure the formation of a clean crack. The ‘Crack inducers (Triangular timber)’ have been installed at bottom of concrete slab to minimize concrete disturbance during initial age. In particular, it is often used to relatively thick airfield pavement compared to road. There are slabs of various thicknesses at the airfield, but the crack inducers are often designed to be installed uniformly without analyzed the joint behaviour to slab thickness. In this paper, the installation of crack inducer considering thickness variation is analyzed and applied. As a result, random cracks or joint freezing wasn’t occurred anywhere on the runway.

As mentioned at the Davos World Economic Forum in 2016, there is now a worldwide wave of waves of the Fourth Industrial Revolution. The flow of government policy and R & D research is also focused on fostering industries based on the Fourth Industrial Revolution. Research in the field of geotechnical engineering can also be a research that lags behind trends if it is not merged with the technology related to the fourth industrial revolution in the future. Therefore, this study analyzed the applicability of the fourth industrial revolution technology in the field of expressway maintenance.

Car-sharing is one of the most popular cases of a shared economy. It is a sustainable service that enhances mobility by renting shared vehicles to meet user's purpose in short-time. Car-sharing has known that it is effective in reducing ownership of passenger cars, reducing traffic congestion, and improving the environment. In Korea, a variety of car-sharing services have been launched, and since 2012, Korea Land & Housing Corporation (LH) has started to introduce HappyCar service for residents of public rental housing complexes nationwide. Public rental housing complexes have three types of complexes, one of which is complex for the low-income households. The purpose of this study is to find out the factors affecting the use of carsharing for low-income people using Poisson regression analysis with 2017 HappyCar usage data. Data including outliers was filtered and explanatory variables (age, sex, and accessibility of public transportation around rental housing complexes) were selected through correlation analysis. The results of this study are expected to be useful for analysis of carsharing low-income users' behavior, demand forecasting, and the establishment of shared transportation policies in the future.

Airport concrete pavement slabs show contraction and expansion behavior due to environmental factors such as temperature and humidity. Among the various environmental factors, temperature is the most influential factor in the concrete slab. However, it is inadequate to consider air temperature or surface temperature as influential factors especially for airport concrete slabs with very large thicknesses. Therefore, this study intends to utilize the equivalent linear temperature difference calculated from the data of the thermometer embedded in 5 depths(50mm, 150mm, 250mm, 350mm, 450mm) on the airport concrete slab. Equivalent linear temperature difference is the temperature difference between the uppermost and lowermost part of the concrete slab, which shows the same behavior due to actual temperature. Since the upper part of the concrete slab is more affected by air temperature than the lower part, the daily temperature range is large. Therefore, the equivalent linear temperature difference increases during the day and decreases at night, and concrete slabs show curl-down during the day and curl-up at night. This daily variation of curling behavior causes a difference in HWD experimental results. The HWD(Heavy Weight Deflectometer) test is mainly performed to investigate the condition of the pavement. And the calculated values are deflection, ISM(Impact Stiffness Modulus), LTE(Load Transfer Efficiency). The equivalent linear temperature difference represents the behavior of the concrete slab by the environmental load, and the calculated values by the HWD test represent the behavior. Therefore, the purpose of this study is to investigate the behavior of concrete slab by combined load including environmental load and traffic load through correlation analysis between these values. This study was supported by Incheon International Airport Corporation(BEX00625) and Korea Airports Corporation.

Demand Responsive Transport (DRT) for the disabled is a special transportation mode for people with disabilities who have difficulties in moving. DRT for the disabled is one of the most important means of transportation for people with disabilities using wheelchairs because it provides door-to-door service with vehicles equipped with wheelchair boarding facilities. The Seoul city operated DRT for the disabled for the first time in Korea in 2003 and currently operates 487 vehicles. This study compared DRT for the disabled with domestic and foreign cases and analyzed usage pattern of DRT for the disabled in Seoul for the frequency of service use and waiting time. The DRT for the disabled usage pattern in Seoul showed that the number of use of weekends was smaller than that of weekdays, and it was used most at noon by the time of day. In the case of waiting time, days except Saturday were similar. On Saturday, the traffic jam was more severe than other days, so waiting time was higher than other days. By the time of day, the waiting time was higher due to the reduction of the number of vehicles in the evening and the nighttime, not the noon which had the highest number of use. As a result of analyzing day by day in four-time zones, it was analyzed that there were spatial differences in waiting time by time zone. This study is expected to be used to reduce the waiting time of DRT for the disabled through DRT for the disabled usage pattern analysis.

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.

Generally, asphalt binder experiences short-term aging during mixing and constructing processes in high temperature environments and long-term aging during the service life after opening the road. Binder aging inside asphalt mixtures incurs changes in strength of asphalt paved roads, which then changes physical properties of the mixture such as cracks and rutting resistance. This study aims to measure bond strength of aging asphalt binder using asphalt bond strength (ABS) test that can measure a bonding force of asphalt binder and aggregate surface using Pneumatic Adhesion Tensile Testing Instrument (PATTI) used previously in the paint industry as a testing method specified in AASHTO TP-91.

Recently, in Seoul, Korea, GPR (Ground Penetration Rader)-based road cavities exploration technology was introduced for the exact cause analysis of road subsidence. The city of Seoul has identified a total of 2504 cavity in 2017 by using the introduced road cavities exploration technology, which shows that the incidence rate of road subsidence is reduced by 67%. However, GPR-based exploration technology is mainly concerned with cavities in the underground of the road pavement, and there is no effective method for areas with a danger zone depth of 1.5m or more and special areas such as narrow sidewalk. The EM (Electro Magnetic) method can be used to check the existence of cavities and poor ground in the underground using information on the location, shape, and electrical conductivity of the anomaly zone in the underground by measuring the electromagnetic field. Therefore, in this study, want to predict with a danger zone area by exploring the underground in the narrow sidewalk or park road by using the EM equipment which is capable of deep geological exploration, non - contact and equipment size change. In the previous research, the underground exploration was performed by simulating the ground and the cavities and the cavities including the metal. As a result, it was confirmed that an electrical resistivity anomaly zone occurred in the cavity regardless of the existence of the metal. Therefore, in order to analysis the applicability of the EM method in the underground cavities area according to the field simulation, this study will conduct the outside experiment by simulating actual sidewalk or asphalt pavement. In the future, the researchers will plan to examine the applicability of various factors such as type, condition and depth of road pavement.

The ride quality (i.e. smoothness) is a key factor for evaluating the construction quality of expressway asphalt pavement. Conventionally, three paving devices are widely used to control the surface layer thickness: leveling sensor (i.e. LS), short-range-surfacing-contact-ski (i.e. SSCS) and long-range-surfacing-contact-ski (i.e. LSCS). However, each of these levelling tools presents one major drawback. In the case of LS, if the original sub-layer evenness is poor, the final asphalt pavement surface and its smoothness will be negatively affected. The SSCS cannot assure satisfactory smoothness when relatively long paving section (in the order of 10 km) are paved. While the LSCS would reduce the drawback of the SSCS, its weight on the one hand and its length on the other discourage its use in the paving site especially for curved sections. In this paper, a next generation pavement smoothness leveling equipment, known as non-contact-digital-ski (i.e. NCDS) was implemented, evaluated and compared to the conventional equipment leveling device. The international Roughness Index (IRI m/km) was measured on sections paved with and without NCDS and the results visually and statistically compared. In addition, for the same sections, the modulus of the pavement layers was computed and compared by means of Falling Weight Deflectometer (i.e. FWD). It was observed that when NCDS is used for asphalt pavement overlay of existing concrete pavement, significant improvement in IRI (i.e. IRI<1.0m/km) and consistently uniform elastic modulus could be achieved compared to the conventional levelling and paving method.

Asphalt pavement is covered over 90% of Korea road network. There are various causes for damage to asphalt pavement such as crack, stripping, and joints et al. A longitudinal joint occurs in an asphalt pavement when a new batch of hot-mix asphalt (HMA) is laid adjacent to an existing lane for maintenance of asphalt road. It is required to pave the width of a road in multiple lanes because paving the full width of the pavement in a single pass is usually impossible. The durability of longitudinal joints in asphalt pavements is strongly related with the pavement service life. This longitudinal joint is generated attachment sites where the old pavement surface and the new pavement surface are adhered to each other. In the short period of time, early cracks are generated due to the adherence failure of the new and old pavement. Rainwater penetrates into cracks at the time of rainfall. The cracks are enlarged to be connected by labeling and pothole generation, resulting in durability of the pavement deterioration of its service life. Therefore, there is a desperate need for a preventive material that can prevent the expansion of cracks in the longitudinal joint. Compare performance sealing tape with tack coating material, the research team is adopted freeze-thaw and wheel tracking loading test methods. The sealing tape shows the better performance than tack coating material under traffic loading and freeze-thawing test.