도로 포장 기술이 발달함에 따라 내구성 확보 등의 구조성능 중심에서 이용자의 승차감 및 소음 저감 등의 기능성 중심으로 변화하 고 있다. 최근 도로 소음에 대한 민원이 증가하고 있고 도로 소음으로 인한 피해를 보상하라는 판결 사례도 증가하고 있다. 이러한 문 제를 해결하기 위해 차량 소음 저감 효과가 우수한 저소음 포장을 적용하고 있다. 본 연구에서는 저소음 배수성 포장과 저소음 비배 수성 포장의 내구성 및 공용성을 평가하였으며, 기대수명 예측을 위해 국내에 있는 배수성 8종, 비배수성 3종의 제품을 이용하여 실내 성능 평가를 수행하였다. 국토교통부의 "아스팔트 콘크리트 포장 시공 지침(2021)"의 배수성 포장 품질기준 및 비배수성 혼합물에 대 한 품질기준에 따라 시험을 진행하였다. 아스팔트 혼합물의 생산, 저장, 운반 및 포설 시 아스팔트의 흘러내리는 양이 적합한지를 평 가하기 위해 드레인다운 시험을 진행하였고, 배수성 혼합물의 골재 비산 저항성을 평가하기 위해 칸타브로 손실률 시험을 진행하였다. 또한 포장의 수분 저항성을 평가하기 위해 인장강도비(TSR) 시험과 소성변형 저항성을 평가하기 위해 동적안정도 시험을 진행하였다. 이후, 배수성 포장의 투수 성능을 평가하기 위한 실내투수계수 시험을 진행하였고, 저소음 포장의 소음 저감 성능을 평가하기 위해 임 피던스 관을 이용한 흡음률 시험을 진행하였다. 시험 결과 모든 종류의 혼합물이 품질기준을 통과하여 충분한 기초 성능을 가지고 있 는 것으로 나타났고, 흡음률 시험의 경우 배수성 혼합물이 평균 0.779, 비배수성 혼합물이 평균 0.638의 흡음계수를 나타내었다. 배수 성 혼합물과 비배수성 혼합물의 평균 공극률은 각각 19.3%, 3.2%로 배수성 혼합물이 비배수성 혼합물에 비해 많은 공극률을 가지고 있어 소음 저감 성능이 비배수성에 비해 우수한 것으로 판단하였다.

국내 고속도로의 콘크리트 포장은 줄눈 콘크리트 포장 공법을 주로 적용해 왔으나 잦은 줄눈부 파손으로 인해 최근에는 공용성이 우수한 연속철근 콘크리트 포장(CRCP)을 확대 적용하고 있는 추세이다. CRCP는 우수한 공용성을 가지고 있지만 다량의 철근 사용으 로 인해 초기 시공비가 높은 단점이 있다. 이러한 CRCP의 단점을 보완하고 공용성을 보다 향상시키기 위해 신개념 철근콘크리트 포 장(ARCP)이 개발되었다. 본 연구에서는 ARCP의 공용성 검증을 위해 고속도로 제14호선 함양~울산 구간에 시공된 ARCP와 동일한 구 간에 시공된 CRCP의 균열조사를 수행하였으며 균열형상 및 균열간격 등을 비교 분석하였다. 분석 결과 ARCP에서 발생한 균열은 CRCP와 비교하여 대부분 직선 형상으로 발생하였으며 균열간격도 보다 균일한 것을 확인하였다. 또한, ARCP에서는 좁은 균열간격, 지그재그 균열, 분리균열 등 부적절한 균열의 발생이 매우 적은 것을 확인하였다. 따라서 ARCP의 균열형상 분석 결과로 보아 ARCP 는 CRCP의 우수한 공용성을 보다 향상시킬 수 있는 공법이라는 것을 검증하였다.

현재 국내에서는 아스팔트 포장의 예방적 유지보수공법의 사용이 미미하며, 시공 기준 또한 부재한 실정이다. 이에 따라 포장가속시 험시설을 활용하여 예방적 유지보수공법 적용에 대한 공용성 변화 분석을 진행하였다. 본 연구에서는 포그씰 A, B 공법에 대해 도포 량을 다르게 시공하여 기능성 인자인 BPN, MPD와 물성 인자인 공극률에 대해 추적조사를 진행하여 공용성 변화를 분석하였다. 주행 횟수의 산정은 가속시험기의 등가단축하중(ESAL, Equivalent SIngle Axle Load)의 관계식을 통해 실제 교통량을 등가단축하중으로 환산 하여 가속시험 주행 횟수를 산정하여 시공 후 공용 1년까지의 성능을 분석하였다. 분석 결과 기능성 인자인 MPD는 차량 주행으로 인 해 점차 감소하였으며, BPN은 시공 직후 포그씰 처리로 인한 미끄럼 저하가 지배적으로 나타났으나 점차 회복되는 것으로 나타났다. 물성 인자인 공극률은 주행 횟수가 증가할수록 포그씰이 포장 표면으로 채워져 공극률이 줄어드는 것으로 나타났다. 도포량별 분석 결과 도포량이 가장 많은 구간에서 저하율이 모든 인자에서 가장 큰 것으로 나타났으며, 두 도포량의 경우 인자별로 미세한 차이는 존재하였으나 대부분 비슷한 경향을 보이는 것으로 확인되었다.

국토교통부는 고속도로 접근성 개선을 통한 지역균형 발전을 위해 남북측과 함께 동서축으로 지속적인 신설 사업을 계획하고 있다. 이에 따라 고속도로 노선의 관리 연장이 증가하고 대부분 산지인 우리나라 지형 특성에 의해 터널 구간도 증가하고 있다. 터널 구간 포장의 경우 환경 조건 등의 영향으로 전이구간에서 파손이 다수 발생하고 있다. 따라서 본 연구에서는 장대터널 구간에서 조사된 PMS 데이터를 분석하여 터널 진입 전 후 PMS 조사 인자별 변화를 분석하였다. 분석 조건은 1) 1km 이상의 장대터널 포장상태조사 자료 분석, 2) SD(Surface Distress), IRI(International Roughness Index), HPCI(Highway Pavement Condition Index) 인자 분석, 3) SD 상세 데이터(균열, 패칭, 스폴링 등) 분석이다. 이를 활용하여 터널 진입 전·후 포장 연장 변화에 대한 분석인자별 변화 검토, 터널 진입 전· 후 분석인자별 평균값 변화 비교, 터널 내 포장의 선형 균열, 패칭, 스폴링 파손 상세 검토를 수행하였다. 분석 결과 터널 진입 후 30~40m 까지 변화가 크게 나타나는 것을 확인하였으며, 평균값 비교 결과 SD 값이 진입 전 후 약 66% 차이가 나타난다. SD 상세데 이터 분석 결과는 균열 및 스폴링 파손 등에 대해 100m 구간 내에 약 3.35m2 정도 패칭보수가 이루어졌다. 장대터널의 경우 터널 입 구와 터널 내부의 환경 조건이 상이하여 전이구간에서 터널 내부보다 파손이 다수 나타나는 것을 확인하였다.

도심지에 시공된 아스팔트 포장은 교통량 증가와 중차량의 가감속으로 인해 포트홀 및 소성변형 등의 파손이 흔히 발생하고 있다. 이러한 아스팔트 포장의 파손을 최소화하기 위해 콘크리트 포장으로 전환하는 공법인 초속경 시멘트 콘크리트 포장 공법과 프리캐스 트 콘크리트 포장 공법이 있으나 고비용으로 인해 널리 적용하기에는 한계가 있는 실정이다. 최근 서울시에서는 신설 중앙버스정류장 에 현장타설 방식으로 연속철근 콘크리트 포장(CRCP)을 시공하였다. 본 연구에서는 인력포설 방식으로 시공한 중앙버스정류장의 CRCP에 대한 공용성을 분석하고자 온도계, 균열유도장치, 철근 변형률계, 콘크리트 변형률계, 변위계, 균열계 등을 포함하는 계측시스 템을 구축하였으며 본 논문에서는 이러한 계측시스템에 대하여 기술한다.

Using porous asphalt in order to reduce traffic noise and increase road safety specially in rainy weather is become a time demand now a days. Traditional dense asphalt can not provide a well mannered drain systems, adequate road capacity and noise friendly environment, which can make harm to roadway, property and ultimately to the life. In contrast, porous asphalt provides a environment friendly, cost effective, high skid resistive and well drains pavement with great durability. Additionally, the ability of porous to decrease the number of crashes both in sunny and wet-weather are up to the mark. In this context, investigate the ability of porous asphalt allows for deeper insights into all the mentioned factors, which help to make a durable, time demandable, more safer pavements in the field of pavement engineering. By combining some lab tests, field tests and analyzing the data, this research offers more accurate and reliable results to lead a pavement situation adaptable.

PURPOSES : The purpose of this paper is to evaluate the performance of MAST composite pavement. METHODS : A Testbed with three different sections with varying pavement materials were constructed: Section 1 (MAST(Multi-Layered Asphalt Surface Treatment) Composite Pavement; RCC(Roller Compacted Concrete)+Modified DBST(Double Bituminous Surface Treatment), Section 2 (Aggregate base+Modified DBST), and Section 3 (aggregate base+General DBST). The structural stability and skid resistance were evaluated using LFWD test and sand patch test, respectively. Moreover, laboratory specimens of four different pavement materials (HMA(Hot Mix Asphalt), Gravel base+DBST, RCC+DBST, and RCC+Modified DBST) were fabricated using and the rutting resistance of each pavement type was evaluated using the MMLS3. RESULTS : As a result of the LFWD(Light Falling Weight Deflectometer) test, the elastic modulus of Section 1 was significantly higher compared to the other section with values between 450 MPa to 650 MPa. Meanwhile, the elastic modulus of Section 2 and Section 3 were almost similar from 50 MPa to 150 MPa. Moreover, sand patch test results showed that Section 1 and Section 2 have an excellent surface roughness with values higher than 0.7 mm but Section 3 has a poor surface roughness with MTD(Mean Texture Depth) value of 0.4 mm. Lastly, based on the results of the MMLS3(third scale Model Mobile Load Simulator) test, gravel base+DBST showed the lowest resistance to rutting among the four specimens, and both RCC+modified DBST and RCC+DBST showed good performance up to 600 loading cycles, but the rut depth increased rapidly until 1,000 loading cycles. CONCLUSIONS : MAST composite pavement(RCC+modified DBST) has superior structural stability compared to general DBST pavement (aggregate base+DBST), has excellent skid resistance with values higher than 0.7 mm, and has similar rutting resistance to that of general dense asphalt concrete pavement. Therefore, exhibiting its good performance in both structural and functional aspects, it can be concluded that MAST composite pavement(RCC+modified DBST) can be an effective alternative for pavement material in Southeast Asian developing countries where support for heavy vehicle loads is required and rutting is likely to occur.

PURPOSES : The purpose of this study was to evaluate the common performance of asphalt pavements, determine the timing of preventive maintenance, and determine the optimal timing of application of the preventive maintenance methods by analyzing PMS data. METHODS : Using PMS data on asphalt pavement performance on highways, we derived the major damage factors and evaluated them according to the public period and traffic level. Among the factors evaluated, we determined those that could be improved by preventive maintenance, calculated the amount of change annually, and derived the timing of the application of the preventive maintenance method through correlation analysis. RESULTS : Among highway PMS data factors, crack variation was found to affect preventive maintenance, which increased rapidly after five years of performance. Traffic analysis showed that changes increased rapidly in the fifth, sixth, and seventh years when AADT exceeded 20,000, exceeded 10,000, and was under 10,000, respectively. Analysis of the amount of crack variation according to the pavement type showed that crack variation increased rapidly in the overlay section compared to the general AP section. CONCLUSIONS : Crack variation is the performance factor that was expected to be effective in preventive maintenance, and the PMS data showed that the initial application time of the preventive maintenance method varied by one year, depending on the traffic volume.

PURPOSES : In this study, surface distress (SD), rutting depth (RD), and international roughness index (IRI) prediction models are developed based on the zones of Incheon and road classes using regression analysis. Regression analysis is conducted based on a correlation analysis between the pavement performance and influencing factors. METHODS : First, Incheon was categorized by zone such as industrial, port, and residential areas, and the roads were categorized into major and sub-major roads. A weather station triangle network for Incheon was developed using the Delaunay triangulation based on the position of the weather station to match the road sections in Incheon and environmental factors. The influencing factors of the road sections were matched Based on the developed triangular network. Meanwhile, based on the matched influencing factors, a model of the current performance of the road pavement in Incheon was developed by performing multiple regression analysis. Sensitivity analysis was conducted using the developed model to determine the influencing factor that affected each performance factor the most significantly. RESULTS : For the SD model, frost days, daily temperature range, rainy days, tropical nights, and minimum temperatures are used as independent variables. Meanwhile, the truck ratio, freeze–thaw days, precipitation days, annual temperature range, and average temperatures are used for the RD model. For the IRI model, the maximum temperature, freeze–thaw days, average temperature, annual precipitation, and wet days are used. Results from the sensitivity analysis show that frost days for the SD model, precipitation days and freeze–thaw days for the RD model, and wet days for the IRI model impose the most significant effects. CONCLUSIONS : We developed a road pavement performance prediction model using multiple regression analysis based on zones in Incheon and road classes. The developed model allows the influencing factors and circumstances to be predicted, thus facilitating road management.

PURPOSES : A mechanistic-empirical (ME) predictive design logic that can compute the reflective cracking life of hot-mix asphalt (HMA) overlaid on top of a composite pavement is proposed herein. METHODS : The overlay thickness design and analysis logic of the HMA were formulated based on the ME concept of reflection crack propagation. Climate data, traffic load data, the pavement material properties, and the thickness of each layer of the pavement are the main inputs for the ME-Reflective Cracking Rate (RCR) prediction algorithm. An Microsoft Excel Virtual Basic for Application (VBA) program was created to aid designers in assessing the expected performance of an HMA overlay design. Calibration was done using data from the Long-Term Pavement Performance (LTPP) sections. Sensitivity analysis was conducted to compare the results yielded by the program and data from a report by the Texas Transportation Institute. RESULTS : The predictive model performance effectively generates the dynamic and relaxation modulus curves. The correlation value of the calibration factors, R2, is 0.79. The calibration factors used for the Asphalt Overlay Thickness Design (AOTD) program and the sensitivity analysis, i.e., k1, k2,, and k3,, are set to 5, 5, and 150, respectively. The sensitivity of the AOTD program affords reasonable results. Additionally, the program yields results similar to the trends presented in a report by the Federal Highway Administration. CONCLUSIONS : The proposed ME design logic is successfully translated into an Excel VBA program, AOTD, which can perform routine assessments of laboratory tests for HMA overlays. The program can effectively perform numerous iterations and computations to predict an HMA overlay. The predictive model can generate reasonable dynamic modulus and relaxation modulus curves for the characterization of HMA overlays. Under the same asphalt binder grade and HMA type, doubling the HMA overlay thickness yields three times the expected reflective cracking service life.

PURPOSES : The purpose of this study was to investigate the characteristics of concrete pavement behaviors and performance depending on the group-axle types of heavy vehicles, such as single-, tandem-, and tridem-axles. METHODS : The concrete pavement performance indices (such as the rate of fatigue cracking and surface smoothness) according to the different group-axle types of heavy vehicles were predicted using the Korean pavement design program. It was assumed that the load magnitude was the same for each axle, and that the equivalent single-axle traffic volumes were the same for the different group-axle types. The concrete pavement stresses depending on the different group-axle types of heavy vehicles were also analyzed using a finite element analysis program. RESULTS : Based on the design criteria, the concrete pavement performance was the highest under tandem-axle traffic and lowest under single-axle traffic, although the difference in performance was not significant. Based on the structural analysis criteria, the tensile stress of the concrete pavement was the largest under the single-axle load and smallest under the tridem-axle load when the load magnitude of each axle was the same. CONCLUSIONS : Based on the results obtained from considering both the design and analysis criteria, it was concluded that the groupaxle types (such as the tandem- and tridem-axle configurations of heavy vehicles) would not increase the stress or decrease the performance of concrete pavements relative to the single-axle configuration.

PURPOSES : The objective of this study is to develop regression models for surface distress (SD), rut depth (RD), and international roughness index (IRI) of Jeju Island local road by analyzing the correlations between the pavement performance and its influencing factors. METHODS : First, the differences between pavements in inland Korea and Jeju Island in terms of performance and influencing factors were investigated. Influencing factors were assigned to pavement sections on Jeju Island using the inverse distance weighting method, and the correlations between the pavement performance and influencing factors were analyzed. As a result, maximum temperature, heat wave days, annual temperature range, precipitation days, precipitation intensity, ESAL, etc. were determined as independent variables for the pavement performance prediction models. Multiple regression analysis was performed to develop the pavement performance models using the selected independent variables. RESULTS : The RD, maximum temperature, and precipitation days were determined to be the independent variables for the SD predictive model. The SD, maximum temperature, annual temperature range, heat wave days, and precipitation days were selected as independent variables of the RD prediction model. In addition, the RD, annual temperature range, heat wave days, precipitation days, and ESAL were selected as independent variables for the IRI prediction model. CONCLUSIONS : As a result of the study, an actual forecast model for SD, RD, and IRI was developed. Based on this model, it is possible to estimate the predictive value of the missing performance data in the studied interval. If the factors affecting performance are managed in terms of maintenance beyond a certain level, it can help those responsible for road maintenance to rationally select the maintenance method and timing.

PURPOSES : This study evaluates the long-term performance of the asphalt overlay designed by the Seoul pavement design method which determines overlay thickness by considering existing pavement conditions, traffic volume, and bearing capacity of the pavement. METHODS : A total of 76 sections including 17 control sections and 59 design sections were constructed under various traffic conditions, overlay thicknesses and asphalt mixtures. The performance of the pavements has been monitored up to 60 months in terms of surface distresses, rutting, and longitudinal roughness. The service life of the pavements was estimated to be the period when the Seoul pavement condition index (SPI) becomes 6.0, i.e., a rehabilitation level. RESULTS : Overall, the service life of the pavements was 72 months in the control and 120 months for the design sections. For relatively thinner overlay sections than designed, the service life reduced significantly; 36 months for 15cm thick overlay and 120 months for 25cm thick overlay. The service life of the pavement in the bus-only lane was 78 months, which is 30 months shorter than that in mixed-traffic lanes. Out of the bus-only lanes, 56% of the pavement along bus stop was deteriorated early to be a poor condition while only 2% of the pavement in a driving lane was degraded to be poor. The overlay with Stone Mastic Asphalt (SMA) in the wearing surface had 38% longer life than that with conventional dense graded mixtures. CONCLUSIONS : Most of the overlays sections designed by the Seoul pavement design method were expected to survive 10 years, except for bus-only lanes. The control sections having 5 to 10 cm thick overlays showed significant lower performance than the design sections. Thus proper thickness and materials considering the characteristics of existing pavement and traffic volumes should be applied to secure the service life of overlays.