PURPOSES : This paper is to deliver an engineering design guide currently unavailable that highway engineers can refer to when they need to determine the safe distance between the starting point of the underground highway in a metropolitan area and the access points of the adjacent highway. METHODS : The distance between two different highway points should be sufficiently far to support the number of lane changes that drivers may take comfortably at the cruising speed in critical traffic conditions. RESULTS : The proper distance for the selected case study is calculated to be 160 and 200 m at the cruising speeds of 40 km/h and 50 km/h, respectively, without significant increase in potential conflicts estimated by the combination of the VISSIM and SSAM analysis. CONCLUSIONS : The proposed design method can be referred in urban metropolitan areas where no specific design guide is yet available, and it would prevent the unnecessary increase in construction costs and encourage private-public partnership highway businesses.

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.

본 연구는 분지구조의 초입부를 가로막는 도로를 신설함에 있어, 일대 마을에 생활기반을 둔 지역주민의 시점에서 도로형식을 결정하는 방안 모색을 위한 연구이다. 이를 위해 본 연구에서는 성토형 도로와 교량형 도로에 대한 선호도 및 선호도 결정요인에 대해 집중하였다. 대상지인 영암군 금정면 안노리 안노마을은 서측을 제외한 동, 남, 북측은 농암산으로 둘러싸인 분지 로 이루어져 있으며, 성토형도로가 계획 중에 있다. 조망권 관련 지역민의 피해정도를 파악하기 위하여 기존 경관, 성토형 도로, 교량형 도로 등 총 3개의 경관을 대상으로 9개의 경관형용사쌍을 선정하여 조사하였다. 연구결과, 기존 경관은 교량형 도로경관과 성토형 도로경관에 비해 경관적 가치가 높게 느껴지며, 교량형 도로경관에 비해 성토형 도로경관에서 더 큰 위압감과 답 답함이 느껴지는 것으로 나타났다. 또한, 내부인과 외부인을 나누어 유형별 특징을 검토한 결과, 외부인은 목적이 되는 대상물 중심으로, 내부인은 목적이 되는 대상물과 더불어 그 주변 환 경과의 관계성을 보는 것을 알 수 있었다. 이는 분지형 마을 입구를 가로지르는 도로의 신설은 지역 주민들에게 심리적 압박감과 불안감을 야기하는 요인이 될 수 있음을 확인할 수 있는 결과이다. 따라서, 분지형 지형구조의 지역에서 도로의 신설이 불가피한 경우, 교량형 도로와 성토형 도로 중 교량형 도로로 신설하는 것이 바람직하다고 판단된다.

PURPOSES : This study aims to investigate the effect of the propagation time of variable message sign (VMS) information and drivers’ detour rate on the VMS performance under non-recurrent traffic states. METHODS: A microscopic simulation model (i.e., VISSIM and VISSIM COM User Interface) was developed at a location where VMS messages were most frequently displaced in 2018 from the Busan Regional Construction and Management Administration. The non-recurrent traffic states realized in this study were one- and two-lane close cases with scenarios involving multiple propagation times from 0 min to 20 min in 2 min increments and detour rates from 0% to 50%, in 10% increments. The measures of effectiveness are the average delay per vehicle, total travel time, and reduction rate of the total travel time based on the average value of 30 multiple simulation runs for individual scenarios. RESULTS:For the one- and two-lane close cases, the reduction rate of the total travel time increased as the propagation time shortened and the detour rate became bigger. The optimal (i.e., 0 min propagation time and 50% detour rate) and worst (i.e., 20 min propagation time and 10% detour rate) scenarios produced 41.1% (8.9 h) and 6.4% (1.4 h) and 26.4% (86.5 h) and 1.4% (4.7 h) of the total travel time for the one- and twolane close cases, respectively. CONCLUSIONS : The study results implied that the late propagation time and the low detour rate might not significantly influence the VMS system. Therefore, it is important to improve the information process time for the shorter propagation time and the reliability of the VMS information for a higher detour rate, which will result in a better VMS system performance.

The highway junctions are the areas where frequent congestion occurs due to a conflict between vehicles entering the main road from the connecting road and vehicles passing through the main road, which is the main target of microscopic and macroscopic traffic flow study. The importance of study on the behavior and the interaction between vehicles at the highway junctions has been emphasized as an essential element of the Cooperation Intelligent Transport System (C-ITS) and Autonomous Vehicle technology. In this study, merging location and time of vehicles in acceleration lane of highway merging area is recorded by aerial videos from drones, and vectormodelling method was developed with merging location (y-axis) and merging time (x-axis). In the vector model, the vector region of the traffic flow is represented by the realistic expressible vector region and the stable entry into the highway. The model is compared with the traffic conditions according to speed, traffic volume, and density in main line and connecting road. This study can be used as a basic data for understanding the behavior of vehicles at the highway junctions and It is expected to be used as an operational indicator for advanced transportation such as lamp metering, C-ITS, and Autonomous Vehicle technology to stable traffic flow on the highway.

The recent increase in truck traffic volume and overloading frequency causes a growing need to re-evaluation of fatigue life of steel bridges. However, the traditional fatigue analysis method, that is cumulative damage method(CDM), has limitation to apply to a number of bridges because the required calculation steps are very cumbersome and complicated. This study investigates the feasibility and applicability of proposed simple fatigue evaluation method based on the equivalent damage method (EDM) in Eurocode to estimate the remaining fatigue life for a highway bridge. The Proposed fatigue life evaluation method is as follows; 1. Calculation of fatigue resistance 𝛾𝑀f and fatigue strength Δ𝜎𝑐 used in design, 2. Calculation of partial safety factor 𝛾𝐹f for equivalent stress range, 3. Calculation of stress range Δ𝜎𝐸2 using influence line, 4. Calculation of damage equivalent factor λ, 5. Review of Fatigue state and evaluation of fatigue life. The specifications of the target bridge are as follows; Location : Gyeongbu Expressway, Design Life : 100yr, Construction year : 2006, Total length : 341m, Type of superstructure : continuous steel box girder. The resulting remaining fatigue life estimated by both EDM and CDM have been compared. Remaining fatigue life of target bridge in 2016 was calculated 365yr(EDM using WIM data in 2014), 334yr(CDM using strain gauge data in 2012 and reflecting 2% annual traffic volume increase, Gil and Kang(2012)). As a result of comparison, The remaining fatigue life using proposed method(EDM) was evaluated about 10% higher than the CDM. This result, because traffic volume increase had not reflected when calculation of remaining fatigue life using EDM. Proposed method(EDM) can evaluate remaining fatigue life more easily and simply than CDM.

Since 2011, a total length of national highway in Korea is 13,797km and 97.6% of total length of national highway system is paved. Particularly, most of national highway has been paved as asphalt concrete pavement. Currently, many maintenance techniques, such as overlay and surface treatments, are applied on existing pavements depending on the failure levels of pavements. One of maintenance techniques is a hot in-place recycling (HIR) that shows features of cost effective and better performance because of the use of 100% recycling of reclaimed asphalt of existing pavement. HIR is widely used in Europe countries and the U.S. It is recommended to rehabilitate the old and distressed asphalt pavement because it is suitable from the environmental perspective and convenient to use when a road is paved. Since 2002, HIR as a maintenance method has been used to rehabilitate the distressed asphalt pavement in National highway in Korea. Recently, a new HIR system, which consists of three pre-heaters, two recycler and one paver, is introduced in maintenance project in National highway. In this paper, HIR mixtures collected from a new HIR system in the field are tested to evaluate their performance in the laboratory test. First, the reclaimed asphalt (RAP) materials and HIR mixtures are collected in the field project site. Second, the quality evaluation of RAP materials, HIR mixtures and rejuvenator are conducted in the laboratory. Test results of RAP materials and HIR mixtures are satisfied with national specification. Rejuvenator used in the project site is classified as RA-5. Based on the limited teste results, it would be concluded that a new HIR system could be produced a satisfied HIR mixtures in the maintenance projects of National highway.

The composition of the deicer sprayed on the highway is spreading over the highway by the scattering or snow removal activity, or car movement and consequently affecting the vegetation environment around the highway. These are the cause of the damage of fruit trees and crops, and also the cause of corrosion of highway structures. The goal of this study is to estimate the detected range of deicer components from a highway. The concentration of the deicer components in gauze and soil were investigated according to the crossing distance from the highway. The data collected were then used to estimate the concentration range of deicer components in a rage of distance up to 100 m from the highway where the deicer was spread. The sample time and weight of gauze were measured before and after installation, and the soil was collected at more than three points in parallel with the highway at the gauze installation point. The components in gauze and soil were investigated in addition to the deicer components (Ca2+, Na+, Cl-) as well as Mg2+ and K+. As Ca2+ and Cl- components of deicer were affected by agricultural use, Na+ component was selected as a tracer and further SAR (Sodium Adsorption Ratio) of soil was analyzed to examine the degree of influence on vegetation indirectly. The gauze concentration was evaluated by the concentration of the deicer ingredient at the background concentration of the blank gauze. The total amount of the deicer sprayed in the study road for 4 months (winter season) was about 93 ton/km. In the gauze test, the spread of the deicer was detected at a distance of 100 m in study area, but the concentration of the deicer in the gauze by distance decreased rapidly within 10 m from the highway. And concentration of the deicer components in gauze and soil came down after rainy season (August ~ Sep.). The results showed that the components of the deicer could be spread widely by the wind. The effective range of the deicer on vegetation based on SAR in soil was estimated to be less than 20 m from the highway. This study examines the concentration changes of the deicer components in gauze and soils and shows that deicer components sprayed on the highway are accumulated and moved over time by wind, snow removal, terrain, water system and land use around the highway.

Some of the deicer ingredients are the same as fertilizer ingredients from agricultural activities. The goal of this study is to distinguish the components of highway deicer from the components used for agriculture. Among the deicer ingredients, Ca and Cl are substances which can be supplied by fertilizer or livestock manure. However, fertilizer and livestock manure contain plenty of nitrogen, organic matter, phosphoric acid and magnesium, including deicer ingredients. The soil physico-chemical characteristics were analyzed according to the distance from the highway. The physico-chemical analysis items of the soil include electrical conductivity, total nitrogen (TN), available phosphate (Av.P), organic matter (OM), ammonia nitrogen (NH4-N), Cation Exchange Capacity (CEC). In the case of effective phosphoric acid, leaching into the subsoil is very low due to various binding mechanisms in the soil. However, it is considered that the compost (fertilizer) applied to the topsoil is mixed with the soil by the tillage or flattening operation. In addition to the organic matter content of the subsoil appear to 10% or more is that in some cases exhibit a similar level as the topsoil. The average soil organic matter content of about 2.6%. This results shows that an excess of organic compost in the study area flows into subsoil and was mixed with the subsoil. The high EC value at the points outside the snow removal effect range level is not considered to be affected by the deicer. The results of the survey showed that the values were differently detected by agricultural activities, and that they should be approached in a complex way in their interpretation.

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.

One of the most important national tasks of the current administration is to realize social value and boost the economy. In the road sector, it is particularly important to ensure the road sectors public good and create jobs based on the Framework Act on the Realization of Public Institutions’ Social Value (Proposal). In regard to job creation in the road sector, however, there has so far been a lack of career management for construction engineers. In this regard, this study used Monte Carlo simulation and analyzed how to estimate the amount of manpower required to efficiently manage engineering human resources in the road sector. Monte Carlo simulation uses random numbers for prediction and estimation, extracts values repeatedly from a probability distribution predefined by the user, and performs tasks on various scenarios. This study made the following assumptions for the analysis: (a) researchers’ abilities were identical; (b) the research project was analyzed on a 1 year basis while technical advice was analyzed on a 9-week basis to reflect the characteristics of the road sector; (c) technical advice had the same probability from Week 1 to Week 52; (d) the amount of manpower required for a project carried over to the next year was input at the beginning of the year; and (e) the largest amount of manpower required at any particular time in a year was calculated and estimated as required manpower. The input variables were an estimated number of project and technical advice in each research field while the output variables were the amount of manpower and technical advice required for each research project. Simulation was performed 10,000 times. An analysis found that required number of manpower for case analysis was 75 as opposed to the current number of 66, assuming that 57 research projects were undertaken and technical advice was provided 223 times. Every sector is making efforts to create social value through various means. The field of construction social overhead capital is no exception. It has undertaken a very important task to ensure the role of roads in public good and create jobs. However, there is still a lack of objective approach to estimate the required amount of manpower. Thus, as done in this study, calculating required manpower through the simulation method would be useful as an objective evidence for job creation.

The purpose of this project is to seek strategic response for the Korea Expressway Corporation(hereinafter referred to as Public corporation) about the change of the fourth industrial revolution. For this purpose, the project scope has 3 phase. 1. Characteristic of the 4thindustrial revolution and the trend of major change. 2. Prospect of Future Expressway and changes related industry. 3. Publiccorporation’s Short-term strategy and detailed challenges. Also, The Project analyzes the KDF and patterns, which directly/indirectly affect the Public Corporation with change of 4th industrial revolution. As a result, Making a Mid-term and Short-term strategy for respond to future change with Structuring Causal Relationships and Deriving Future Scenarios. Moreover, we focuses on a shift in the number of key changes in the 4th industrial revolution and the first consideration to derive a significant change in the direction of change in the 4th century, focusing on trends that will not change the trend in 10 years, rather than 10 years later. First, The 4th industry revolution is not just point of view that integration of technology such as IOT,AI but Motivation that Creating the innovation in the whole society with huge change of social system. So executing Macroscopic analysis for formation of sympathy. Second, creates core changes drivers individual, businesses, and national level drivers in future trends. And the strategic direction that road's role and function at future society are reflected in the public corporation's strategic tasks. Thrid, For prospect of future expressway, reviewing public corporation's existing research data. As a result, Preventing duplicate researches and enhance research efficiency. Fourth, an analysis of the present situation Through expert review of the 4th industry revolution and future development direction by convergence based on a current road map. Considering the change in the social and social environment, prospect future outlook with Deduction of change drivers that will not changed after 10years. Fifth, focus on human desires and values, technological innovation, solving problems, converging technology culture, solving social issues, and responding to changes in social issues. In order to realize this, it is possible to communicate in storytelling so that ordinary people can easily understand the changes in the area. Based on the scenario, we prepared for the future of the Korea Expressway Corporation by setting up a total of 15 detailed tasks based on the scenario and the fact that 15 different aspects of the project are based on the scenario.

PURPOSES : The purpose of this paper is to analyze the change in lane reflection performance through lane washing and sweeping on highway lanes. METHODS: This paper compared and analyzed the changes in lane reflection performance before and after lane washing and sweeping. The research method was as follows. First, we selected four research sites on the Gyeong-bu Highway. Second, the parameters affecting lane reflection performance are classified into luminance, brightness, and number of glass beads. Third, the change in reflection performance was measured after washing /sweeping at the same place after studying 60m of the unwashed/unswept area. Fourth, the measurement results were compared and analyzed before and after lane washing/sweeping. RESULTS: The results of this study are as follows. First, lane washing improved the luminance and brightness by 4.2~21.4% and 1.4~5.1%, respectively, and reduced the number of glass beads per wash by 0.2~1.2%. Second, lane sweeping improved the luminance and brightness by 2.3~8.5% and 0.8~2.3%, respectively, and reduced the number of glass beads per sweep by 0.8~4.9%. CONCLUSIONS : By comparing the results of lane washing and sweeping, it was found that compared to lane sweeping, lane washing improved the luminance and fewer glass beads were dropped.

PURPOSES: Case studies of an asphalt-overlay project with a performance-based contract method were conducted on a national highway in Korea to evaluate the effect of the method on asphalt pavement maintenance. This study evaluated the procedure of the performance-based contract method. METHODS: In this study, an asphalt-pavement maintenance project for a national highway was assessed with a performance-based contract to investigate the advantage of the new contract procedures. This is the first trial applying the performance-based contract to a pavementrehabilitation project in Korea. In the four case studies, the warranty period of the performance-based contract was designed for seven years. The research team monitored the construction site to compare the normal contract method with the performance-based contract method. The case studies’project sites were investigated after the end of the construction. RESULTS : Based on the limited case studies, the performance-based contract method could extend the service life of the asphalt pavement and reduce the pavement-maintenance budget because the quality control was well managed by the contractors. However, a few construction laws would be necessary to apply the performance-based contract method in the future. CONCLUSIONS : Using the performance-based contract, the construction company made great efforts to guarantee the warranty period and to apply the optimal maintenance method, based on the pavement distress condition. The contractor and the agency would need to understand the new performance-based contract system for it to be activated. Therefore, a proper education program for the performancebased contract system would be needed to educate the stakeholders regarding the procedures and their effects on the pavement management and maintenance.

PURPOSES : This study analyzed the difference in a driver’s workload between using a driving simulator and field driving in tunnel, highway.METHODS: Based on the literature review, it was found that a driver’s workload could be quantified using biosignals. This study analyzed the biosignal data of 30 participants using data collected while they were using a driving simulator and during a field test involving tunnel driving. Relative energy parameter was used for biosignal analysis.RESULTS : The driver’s workload was different between the driving simulator and field driving in tunnels, highway. Compared with the driving simulator test, the driver’s workload exhibited high value in field driving. This result was significant at the 0.05 level. The same result was observed before the tunnel entrance section and 200 m after the entrance section.CONCLUSIONS: This study demonstrates the driving simulator effect that drivers feel safer and more comfortable using a driving simulator than during a field test. Future studies should be designed considering the result of this study, age, type of simulator, study site and so on.

PURPOSES: In this research, an SB3-level roadside barrier for a highway transition zone that meets the newly established guide Installation and Management Guide for Roadside Safety Appurtenance is developed. Its performance is evaluated by a numerical simulation and real-scale vehicle impact testMETHODS: The commercial explicit dynamic software LS-DYNA is utilized for impact simulation. An FE model of a passenger vehicle developed and released by the National Crash Analysis Center (NCAC) at George Washington University and a heavy goods vehicle (HGV) model developed by the TC226/CM-E Work Group are utilized for impact simulation. The original vehicle models were modified to reflect the conditions of test vehicles. The impact positions of the passenger vehicle and truck to the transition guardrail were set as 1/2 and 3/4 of the transition region, respectively, according to the guide.RESULTS : Based on the numerical simulation results of the existing transition barrier, a new structural system with improved performance was suggested. According to the result of a numerical simulation of the suggested structural system, two sets of transition barriers were manufactured and installed for real-scale vehicle impact tests. The tests were performed at a test field for roadside safety hardware of the Korea Highway Corporation Research Institute.CONCLUSIONS: The results of both the real-vehicle impact tests and numerical simulations of the developed transition barrier satisfied the performance criteria, and the results of numerical simulation showed good correlation with the test results.

PURPOSES : The purpose of this study is to analyze the performance life of hot central plant recycling (HCPR) and hot in-place recycling (HIR) pavements applied to the National Highway for the past 20 years and compare it with conventional hot-mix asphalt (HMA) pavement. METHODS: In order to analyze the performance life of recycling asphalt pavements, a comprehensive literature review was conducted to investigate the government law and official system for the use of recycling asphalt pavement in Korea and foreign countries. Next, the application information of using a hot central plant recycling and hot in-place recycling pavements in the national highway is collected from the database of pavement management system (PMS) and then their field condition is visually surveyed. Finally, the performance life of recycling asphalt pavements in the national highway is analyzed and compared with conventional hot-mix asphalt pavement. RESULTS: Institutions are encouraging the promotion of using recycled asphalt pavement through various legal systems in Korea as well as abroad. Based on analysis results for the average performance life of hot central plant recycling pavement applied to the national highway, the average performance life is estimated to be 10.2 years. However, the average performance life of in-place recycling pavement is estimated to be 6.5 years. However, it is expected to increase performance life after the HIR construction system is modified. CONCLUSIONS : Based on the limited data analysis of the performance life of recycled asphalt pavements, HCPR shows similar performance life to conventional asphalt pavement but HIR shows shorter performance life than conventional asphalt pavement. However, it is noted that all performance life data is very limited and it should be monitored and analyzed further.

도시지역에서 녹지의 역할은 도시민들의 스트레스 완화효 과뿐만 아니라 도시기온 저감, 이산화탄소흡수, 증발을 통한 습도조절, 그늘제공의 도시환경개선에도 큰 역할을 수행하 며, 도시민의 건강증진측면에서 녹지의 중요성이 더 부각되 고 있다. 녹지 내 수목의 광합성 및 다양한 원인에 의해 발생하는 공기이온은 실제적으로 인간의 건강에 긍정적인 영향 을 미치며, 오염물질을 저감하는 것으로 밝혀졌음에도 불구 하고 그에 대한 관심은 상대적으로 낮은 것으로 판단된다. 이에 본 연구에서는 도심지 내 아까시나무가 우점되어 있는 근린공원에 이온지수의 특성을 분석하여 향후 근린공 원의 건강성증진을 위한 생태적 관리의 기초자료로 활용하 고자 하였다. 연구대상지는 서울 은평구에 위치한 구산근린공원을 대 상으로 진행하였다. 대상지의 분류는 10m×10m으로 격자 그리드를 형성하여 가로 A~Z, 세로 1~21로 구분하여 가로· 세로 30m마다 측정지점을 선정하였으며, 식생이 바뀌는 특 이점을 추가로 조사를 하였다. 식생현황과 경사도, 사면방 위, 습윤지수도, 토지이용유형, 토지피복유형, 표고를 조사 한 후 측정지점마다 양이온과 음이온을 각각 5반복으로 측 정하였으며, 동시에 기온, 상대습도, 풍속 및 복사량을 측정 하였다. 단순 음이온 또는 양이온의 변화는 동일한 경향을 나타낼 것으로 예상되므로 이를 보정하기 위하여 이온지수 로 환산하여 분석을 실시하였다. 측정기간은 9월로 측정시 간대는 10시부터 16시까지 진행하였다. 29개 지점의 평균 LAI 지수는 3.08로 측정되었으며, 기 온의 경우 25.8℃로 측정되었다. 상대습도는 69.4%로 측정 되었으며, 일사량과 순복사량은 각각 67.26W/m2, 57.48로 측정되었다. 측정지의 식생환경은 교목의 경우 아까시나무 가 우점하고 있었으며, 아교목층의 경우 단풍나무가 주를 이루었으며, 산벚나무, 가중나무, 밤나무 등이 출현하였다. 관목에서는 국수나무가 우점하고 있었으며, 간헐적으로 개 나리, 신갈나무 등이 출현하였다. 총 29지점을 대상으로 평균 양이온은 350±50ea/cm3 으 로 발생하였으며, 가장 낮은 지역은 S11로 분석되었다. 가 장 높은 지역은 G5로 평균보다 약 150ea/cm3정도 높게 분 석되었다. 이는 도로와 인접해 있고 교목층이 없어 높게 나 온 것으로 사료되었다. 음이온의 경우 430±100ea/cm3 으로 발생하였으며, 가장 높은 지역은 S11 지역으로 평균보다 약 100ea/cm3 정도 높게 발생하였으며, 가장 낮은 지역은 R11로 평균보다 약 200ea/cm3정도 낮게 발생하였다. 팥배나무가 우점하고 있 는 지역으로 다른 지역에 비해 상대습도가 많이 낮았기 때 문에 나온 결과로 사료된다. 이온지수의 경우 가장 높은 지역은 S11로 다른 지역에 비해 약 1.2정도 높은 것으로 조사되었으며, 이는 다른 지역 에 비해 음이온 발생량이 높고, 상대습도가 높았으며, 양이 온 발생량이 낮았기 때문이었다. 가장 낮은 지역은 R11로 상대습도가 가장 낮았으며, 음이온 발생량 또한, 가장 낮게 측정되어 나온 결과로 사료되었다. 도심지 아까시나무림에 격자그리드를 형성하여 이온지 수 특성에 대한 연구로서 습도가 변화하는 지점에서는 이온 지수에 차이가 나타나는 것으로 분석되었다. 그러나 본 연 구는 단순 여름철에 측정을 실시하여 계절변화에 따른 이온 지수변화를 고려하지 못하였다는 제한점이 존재하였다. 이 에 따라 차후 계절변화에 따른 연구와 조사가 이루어져야할 것으로 판단되어진다.

국내 고속도로 중 약 60%가 콘크리트로 시공되어있으며, 이 중 많은 물량이 설계수명인 20년을 초과하여 공용되고 있는 실정이다. 또한 오랜 기간의 하중 재하로 인해 구조적인 능력이 한계에 이르러 최근 국내 고속도로 포장에서 많은 파손이 발생 되고 있다. 실제로 최근 고속도로 포장의 노후화 및 열화 현상이 지속적으로 빠르게 발생하고 있으며, 보수구간의 재파손 사례 또한 증가하고 있어 이에 대한 대비가 절실히 필요하다. 현재 고속도로의 도로포장은 PMS(Pavement Management System)를 기반으로 한 HPCI(Highway Pavement Condition Index)를 유지보수 우선순위 선정 및 개괄적인 보수공법 결정 등에 기준으로 체택하고 있다. HPCI는 주행 평탄성을 표현하는 지수인 IRI(International Roughness Index)와 포장의 표면에 발생한 손상 량을 표현하는 SD(Surface Distress)로 구성 되어 있다. 본 연구에서는 이러한 연구의 일환으로 포장상태에 영향을 줄 수 있는 다양한 요소들을 고려 한 미래의 IRI와 SD를 예측할 수 있는 모델을 Network Level 차원에서 개발하고자 하였다. 본 연구에서 개발 된 모델은 다양한 요소를 고려하기 위하여 기존의 HPCI에 사용되었던 IRI, SD 이외 포장의 재령, AADT 교통량, 제설제 사용량, ASR 등급, 환경 인자(평균기온, 연교차, 강수량, 강수일수, 눈일수, 신적설, 영하일수)를 고려하여 개발하고자 하였으며, 각 변수들에 대한 통계분석을 실시하여 각 변수들 간의 관계를 분석하고 이를 이용해 IRI와 SD 각각의 예측모델을 개발하였다. 이러한 연구들을 통해 본 연구의 범위 내에서 다음과 같은 결과가 도출되었다. Δ      재령  제설제사용량    연교차  강수일수  신적설  눈일수       여기서, Δ    등급  평균기온  연교차  강수량  강수일수  신적설  눈일수       여기서, Δ의 경우 현재 IRI, ASR 등급, 연교차 순으로 영향을 받았으며, Δ의 경우 연교차, 평균기온, ASR 등급 순으로 영향을 받은 것을 모델을 통해 알 수 있었다. 본 연구의 결과를 통해 각각의 변수들이 IRI와 SD에 미치는 영향을 파악하여 미래 포장상태를 예측 할 수 있을 것으로 기대된다.