산업 발전에 따라 도로 연장이 지속적으로 증가하면서 폐 아스팔트 발생량이 늘어나자, 국내에서는 순환골재를 의무적으로 사 용하도록 관련 규정을 마련하였다. 현장 플랜트에서 순환 아스팔트 혼합물을 생산할 때 재생첨가제를 투입해야 하는 경우, 국 토교통부 “아스팔트 콘크리트 포장 시공 지침“에서는 재생첨가제와 아스팔트를 동시에 투입하도록 명시하고 있다. 그러나 혼합 시간이 부족하거나 혼합 과정이 불량할 경우, 재생첨가제가 균일하게 분산되지 않아 혼합물 품질이 저하될 우려가 있다. 이에 본 연구에서는 기존의 건식 혼합 방식에서 발생하는 문제점을 해소하고자, 아스팔트 플랜트의 Pre-Mixer를 활용하여 아스팔트 바인더와 첨가제를 사전에 혼합하고, 혼합 시간을 달리한 시료를 추출하여 DSR(Dynamic Shear Rheometer) 장비를 통한 MSCR 시험을 수행하였다. 그 결과, 혼합시간이 증가함에 따라 Jnr 값은 증가하고, %Recovery 값은 감소하는 경향이 확인되었 으며, 혼합 시간이 바인더 특성 변화에 유의미한 영향을 미치는 것을 확인하였다. 추가적으로 t-검정을 통해 이러한 경향의 통 계적 유의성을 검증한 결과, Jnr 값은 3-5분, 7-9분, %Recovery 값은 1-3분, 3-5분, 7-9분 구간에서 p값이 0.05 이상으로 나타 나 통계적으로 유의미한 차이가 없었다.

This study aims to reduce the use of chloride-based deicers by analyzing their residual quantities on road surfaces. The freezing conditions of road surfaces were quantitatively defined using needles of consistent weight and diameter, and indoor experiments were conducted to observe changes in surface conditions caused by residual deicers under various temperatures. To validate the equipment, a deicer currently used in Korea was applied to granite plates, and the correlation between the application rates and salinity measurements obtained using the SOBO3+ device was analyzed. Subsequently, the device was employed to measure salinity changes over time by assessing the variations in residual deicer quantities on roads with different traffic volumes and application rates. To identify issues in current reapplication methods, the deicer was reapplied at 2-h intervals, and the resulting changes in salinity were monitored. Results of laboratory experiments revealed that the interval for surface state changes decreases with the temperature despite increased deicer usage, and that similar surface change patterns are presented at higher (-2 °C, -4 °C) and lower temperatures (-6 °C, -10 °C). Across all temperatures, the coefficient of determination for the surface-change graph is approximately 0.90. Equipment verification shows that 10% of sodium chloride is underestimated, whereas aqueous calcium chloride is accurately measured and no correlation is indicated between measurement accuracy and road surface temperature. Field experiments confirmed that the deicer dispersion rates increases with the traffic volume. Furthermore, the final salinity increases after the reapplication of the deicer, except in cases of high traffic volume, and that repeated applications with reduced spray amounts are more effective than single applications with higher spray amounts under low traffic conditions. Based on the findings obtained, a plan to reduce deicer usage is proposed. Future research should incorporate additional variables that affect deicer loss and surface condition changes to further refine the results.

This study evaluates adhesion strength under various conditions to ensure adhesion performance during asphalt-pavement maintenance. The adhesion performance of a tack coat varies under various conditions. Therefore, to evaluate its curing behavior, several tests, i.e., evaporation residue rate, tracking, tack-lifter, and shear bond strength tests, were conducted based on the type, amount, and curing time of the tack coat.The result of the evaporation residue rate test shows that, except for the SSC tack coat, RSC-4 and modified tack coats require similar curing times, even though the modified tack coats have a lower moisture content. Additionally, based on the evaporation residue rate, the tracking and track-lifter test results show that approximately 75% curing is required to prevent the loss of the tack coat during asphaltpavement maintenance. After maintenance work is completed, the shear bond strength was measured to evaluate the curing properties of the tack coat. The results show that the amount applied, curing degree, and shear bond strength are proportional, whereas the modified tack coat indicate a significant difference in the strength increase rate depending on the curing degree. Additionally, when dust is attached to the surface of the tack coat, the difference in strength exceeds 20%, depending on the attachment ratio.To achieve the best adhesion performance by the tack coat during maintenance work, the loss of the tack coat should be prevented by implementing the exact curing time determined experimentally, regardless of whether the tack coat is modified, and the surface where the tack coat is applied should be cleaned before application.

This study investigated the tracking loss rate and shear bond strength under various conditions to evaluate the properties of a trackless tack coat used in asphalt pavement maintenance and conducted a field investigation in which the trackless tack coat was used. Typically, the loss rate and bond strength of a tack coat depend on various conditions. Therefore, to evaluate the loss rate of the tack coat, a wheel-tracking attachment loss rate and tack lifter test were conducted by simulating high-temperature exposure conditions, and the shear bond strength was measured according to the surface condition of the bottom layer. In addition, field investigations of cracks, rutting, and potholes were conducted at 11 sites five years after the application of the trackless tack coat. The results of the wheel-tracking loss rate evaluation showed that the loss rate differed depending on the conditions of the bottom layer, and the loss rate of the trackless tack coat was very low at the same temperature as that of the rapid strength concrete (RSC). In addition, in the results of tack lifter test at 65℃, which had the highest loss rate by wheel tracking loss rate test, it was found that loss rate of trackless tack coat was 0%–29% lower than that of RSC for the same exposure time. As a result of evaluating the effect of the bottom layer's condition on the shear bond strength, it was found that the trackless tack coat was about 20% higher than RSC under the same conditions. In addition, when foreign substances such as dust were present in the bottom layer, the shear bond strength was reduced by approximately 28%. Field investigations of the trackless-applied section showed that potholes and rutting did not occur, and alligator cracks and linear cracks occurred in some sections; however, it was judged that there was little direct relationship with the trackless tack coat. The trackless tack coat was found to have a slight loss owing to tracking, even at relatively high temperatures, and the shear bond strength was excellent. In addition, if the construction process is properly conducted, an advantage will be attained in securing the performance life of asphalt pavements.

Pavements have historically been used for mobility, but their usage in cities is steadily increasing owing to social and cultural development. Urban development is rapidly accelerating, primarily because of the concentration of the urban population. Additionally, the effects of the urban heat island are intensifying owing to global warming. One of the main factors contributing to this phenomenon is the increase in impermeable layers, such as asphalt and concrete pavements, in city centers. Various technological developments have been conducted to reduce the effects of urban heat islands. This study developed a moisture-retaining asphalt that absorbs moisture by incorporating a highly super-absorbent polymer (SAP) into a porous asphalt mixture, with the aim of alleviating the urban-heat-island effect. The porous asphalt mixture was designed accordingly. When the mixing design was completed, tests for the tensile strength ratio (TSR), asphalt wheel tracking, and indoor water permeability were conducted on the porous asphalt. Moreover, Hamburg wheel tracking and dynamic water acupuncture tests were performed to evaluate the compatibility of SAP moisture-retaining asphalt, and the results were as follows: Depending on the type and content of SAP, we confirmed that the TSR and permeability coefficient decreased as the amount of SAP increased, resulting in a decrease in durability. In addition, thermal characteristics and simulations showed that the SAP asphalt mixture would have a heat island reduction effect. In this paper, guidelines for the blending design of SAP moisture-retaining asphalt are presented with the aim of alleviating the urban heat island phenomenon by ensuring durability while simultaneously reducing surface temperatures.

동절기에 시민들의 안전 및 편리성을 위하여 도로 유지 보수는 필수적이다. 유지 보수 중 도로의 눈 및 얼음을 제거하기 위해서는 제설제를 살포하는 것이 가장 일반적이다. 하지만, 국내의 제설제 재살포 시기 및 양에 대해서는 연구된 바가 존재하지 않는 실정이기 때문에 제설제 살포 후 녹은 눈이 재결빙이 되는 소요시간이 3시간이라는 점을 참고하여 현재 국내에서는 기후 변화에 관계없이 3시 간마다 초기에 살포한 양을 제설제를 살포하거나 현장 감독자의 주관적인 판단으로 제설제 살포량을 결정하여 제설제 살포를 실시하 고 있다. 이렇게 무분별한 제설제 살포는 과다 살포로 이루어져 환경 및 구조적 문제를 야기할 수 있으며 위 문제를 해결하기 위해서 는 도로에 잔존하고 있는 제설제의 양을 파악하고 무분별한 제설제 살포를 막아야할 필요가 있다. 따라서 본 연구에서는 도로에 물을 살포하여 전기전도도를 이용하여 염분을 측정하는 장비인 SOBO3+를 이용하여 도로의 잔존염분량을 측정하기 전, 국내 고속도로에서 사용되는 제설제와 SOBO3+ 장비와의 상관 관계를 분석하여 장비 검증을 실시하였다. 실험은 국내에서 가장 많이 사용되는 살포 방법 인 습염식 살포 방법을 참고하여 고형 염화나트륨과 30% 염화칼슘 수용액을 사용하였으며 정확한 염분 측정치를 얻기 위하여 매끄러 운 화강판 및 고형 염화나트륨을 모두 용해시켜 측정을 진행하였다. 제설제 살포량은 염화나트륨의 경우 SOBO3+가 최대 50g/m² 까지 밖에 측정이 가능하다는 점을 참고하여 10~50g/m² 범위에서 살포 밀도를 10g/m²씩 변화시켜가며 측정한 결과, 살포량 대비 약 10% 과 소평가되어 측정됨을 확인하였다. 또한 염화칼슘 수용액의 경우 국토교통부 도로제설업무수행요령을 참고하여 국내 습염식 살포 기준 에서 염화칼슘 수용액 살포량이 최대 20g/m²을 초과하지 않아, 10~30g/m² 범위에서 살포 밀도를 10g/m²씩 변화시켜가며 측정한 결과, 살포량 대비 약 70% 과소 평가 되는 것을 확인하여 30% 염화칼슘 수용액을 정확하게 측정하는 것을 확인하였다. 또한 노면 온도가 측정 성능에 영향을 미치지 못하는 것을 확인하였다.

택코트란 아스팔트 포장 공사 시 기존 아스팔트층과 신설 아스팔트 층 사이에 부착성을 증가시키기 위하여 사용되는 재료이다. 교통 하중으로 인해 포장 경계면에서 수평전단응력 및 수직인장응력이 발생하게 되는데 택코트의 유실, 양생 부족 등의 문제로 접착 성능 이 부족하면 포장층의 분리, 밀림과 같은 도로 파괴가 형상이 나타날 수 있다. 현재 국내에서는 국토교통부 아스팔트 콘크리트 포장 시공 지침에 택코트 살포량에 대한 기준은 존재하지만 기존 및 신설 아스팔트 포장층 사이에 택코트의 접착강도에 대한 기준은 존재 하지 않는 실정이다, 이는 접착강도 특성이 분석되지 않은 택코트를 사용함에 따라 아스팔트 포장의 공용성 측면에서 문제를 초래할 수 있다. 따라서 본 연구에서는 PG등급이 다른 택코트 4종류에 대한 인장 및 전단접착강도를 확인하기 위하여 인장접착강도 시험, 전 단접착강도 시험을 진행하였다. 택코트의 양생정도에 따른 접착강도 특성을 확인해보기 위하여 택코트의 수분이 증발됨에 따라 중량 변화가 없는 상태를 양생 100%로 하여 양생 0%, 50%, 100%로 진행하였으며, 살포량은 국토교통부 아스팔트 콘크리트 시공 지침에 따 라 0.5ℓ/m2로 진행하였다. 사용된 택코트 종류에 관계 없이 양생 정도가 증가함에 따라 접착강도는 증가하는 추세를 보였으며, 인장 및 전단접착강도 시험에 관계없이 초기 양생(양생 0%~50%)보다 양생 50% 이후에서의 더 높게 강도가 발현된 것을 확인하였다. 또한 PG등급이 높은 택코트가 인장 및 전단접착강도에 관계없이 접착강도 성능이 우수한 것을 확인할 수 있었다. 추후 택코트의 종류를 추 가하여 PG등급이 분류가 이루어진 후에 접착강도 시험을 진행하여 결과를 확인할 예정이다.

PURPOSES : This study was conducted to evaluate the physical properties of the RAP 50 asphalt mixture containing polymer modified rejuvenator and warm-mix additive to improve the recycling rate of RAP and reduce CO2 emission. METHODS : Mix design of Polymer Modified Warm-mix Asphalt Mixture(RAP 50), and Hot Mix Asphalt Mixture(RAP 30) were produced and the properties of asphalt mixture such as Marshall Stability, ITS, Deformation Strength, TSR, and Dynamic Stability were compared between the two asphalt mixtures. RESULTS : The RAP 50 asphalt mixture showed superior or similar performances compared to the RAP 30 asphalt mixture in all the tests conducted. The results of the Marshall stability and dynamic stability in particular were 13,045N and 3,826 pass/mm, which were 11.37% and 76.7% greater than the RAP 30 asphalt mixture, which indicated that high plastic deformation resistance may be expected. CONCLUSIONS : The results obtained from laboratory tests on the two types of mixtures indicated that the use of polymer modified rejuvenator and warm-mix additive not only allows to increase the proportion of RAP but also improves its properties under lower temperature condition than RAP 30 asphalt mixture. Additionally, it was confirmed that plastic deformation resistance was high and moisture resistance and crack resistance were improved for a RAP 50 asphalt mixture.

PURPOSES : The process of extracting and recovering an asphalt binder from an asphalt mixture is harmful to the human body and can affect the properties of the asphalt binder owing to the presence of residual solvent quantities. This study was conducted to determine the properties of aged asphalt binders based on rejuvenator content without extracting and recovering the asphalt binders using RAP mortar. METHODS : After extracting and recovering aged binders from waste asphalt, a rejuvenator was added at a certain rate to evaluate the physical and rheological properties of the binder based on the added amount. RESULTS : When the rejuvenator content was greater than necessary, the absolute viscosity was not properly measured owing to the behavior of the rejuvenator. The phase angle was measured to be almost 90°, thus indicating that it acted as a liquid . In addition, the shear strain and nonrecovery compliance also increased significantly. CONCLUSIONS : If an excess rejuvenator quantity was added to the aged binder, the absolute viscosity was not properly measured, the phase angle was measured to be almost 90°, and the shear strain increased significantly. It is also necessary to conduct the same tests on different types of RAPs to ensure that the results of this study are reasonable.

PURPOSES : This study was conducted to prevent road thinning ice caused by abnormal weather conditions. METHODS : The appropriate amount of de-icer spread rate was verified by presenting the appropriate amount of snow removal agent spraying criteria for the thickness of the water film, owing to abnormal weather phenomena (fog, frost), and applying the standards to the site. Furthermore, we present a method to utilize residual salt, by quantifying the surface state changes according to the amount of deicer. RESULTS : Precautionary spread experiments to prevent road thin ice caused by abnormal weather conditions, indicated no freezing from 7.6g/m2 at 2℃-4℃ but 11.1g/m2 was suggested as a step higher considering external environmental variables. The amount of spraying was presented in two sections of rainfall(freezing rain). It is 17.7g/m2 at 0-7℃, 33.3g/m2 at -7~ -15℃, and 44.4g/m2 and 51.1g/m2 at non-urban, respectively. CONCLUSIONS : The criteria were divided into air temperature and road temperature standards, so that they could be distributed according to the temperature standards that meet the conditions, and the criteria presented were confirmed to be effective in preventing road thinning ice. If the road manager adopts Safety Line, which is suggested by utilizing the amount of residual salt on the road, it is believed that it can help determine the additional deicer.

PURPOSES : This study aims to reduce the urban heat island phenomenon via utilization of porous asphalt pavements. METHODS : One of the many known functions of porous asphalt is that it reduces the urban heat island phenomenon. Indoor experiments were conducted to compare the surface temperature of sprinkled dense-graded and porous asphalt and outdoor experiments were conducted to verify the difference between the two asphalt pavements under external conditions. RESULTS : The results of the indoor experiment demonstrated that the temperatures of the two pavements were similar and that the porous asphalt pavement exhibited low temperature when sprinkled; the temperature of the porous asphalt was approximately 2 °C lower than that of the dense-graded asphalt pavement. The results of the outdoor experiment showed that the peak temperatures of the two pavements were approximately the same as usual. However, it was confirmed that the surface temperature of the porous asphalt pavement at night after sunset was lower than that of the dense-graded asphalt pavement and that the peak temperature dropped for approximately 1~2 days after the rainfall.. CONCLUSIONS : Porous asphalt pavement has a lower surface temperature than normal dense-graded asphalt pavement, under the presence of moisture in the pavement. In addition, it was confirmed that the lower surface temperature of the porous asphalt pavement is due to the low heat emission of the pavement at night. Accordingly, it is believed that the application of the porous asphalt pavement will not only have known effects but also significant impacts on the reduction of urban heat island phenomena.

서 론 빠른 경제성장과 함께 <2016년 국토교통부> 자동차 등록대수는 2180만을 돌파하였다. 이처럼 많은 차량들이 도로를 사용하게 됨에 따라 기존의 아스팔트도로와 콘크리트도로가 많이 노후와 되어있는 추세이며, 이에 도로의 유지.보수 관리의 중요성이 높아지게 되었으며, 유지.보수간에 가장 많이 사용되는 공법 중에 하나인 덧씌우기 공법에 사용하는 택코트의 성능을 검토하기 위해 수행되었다. 실험 방법 및 사용재료 2.1 사용재료 실험에 사용된 택코트는 일반적으로 사용되어지는 RSC-4와 택코트 필름을 사용하였으며, 부착강도를 측정하기 위해 양생시간을 동일하게 하여 Pull of test를 통해 부착강도를 측정하였다. 2.2 실험 방법 휨몰드와 마샬 몰드를 사용하여 각각 택코트 RSC-4와 필름을 사용하여 공시체를 제작하였다. 1층 다짐 후 24시간 양생 후 2차 다짐을 한 후에 48시간 부착강도를 측정하였다. 그림1은 본 실험에 사용된 시편의 제작과정이며, 그림2는 부착강도 테스트 후의 모습이다. 결과 및 고찰 3.1 동일한 양생조건에서 콘크리트 위에 부착한 택코트 종류에 따른 부착강도 그림4은 휠트래킹 몰드로 만든 콘크리트에 부착한 택코트 종류에 따른 부착강도를 나타낸 그래프이다. 3.2 동일한 양생조건에서 아스팔트 위에 부착한 택코트 종류에 따른 부착강도 그림 5는 마샬 몰드로 만든 아스팔트 공시체 위에 부착한 택코트 종류에 따른 부착강도를 나타낸 그래프이다. RSC-4의 경우에는 살포 후 30분간 상온양생을 실시하였다 결 론 일반적으로 사용되어지고 있는 택코트 인 RSC-4의 경우 유화아스팔트라는 성질 때문에 충분한 양생이 필요하여 공기가 늘어나게 되어 실제 현장에서 규정에 맞게 사용하기가 힘든 실정이다. 도로 유지.관리 공법중 하나인 덧씌우기 공법에 사용되는 택코트의 종류와 부착하는 재료에 따른 부착 강도평가 실험결과는 다음과 같다. 1) 콘크리트 위에 각각 RSC-4와 택코트 필름을 부착하여 Pull-off-test 장비를 이용하여 부착강도를 평가한 결과 각각 0.77, 0.76 으로 비슷한 결과를 나타냈다. 2) 아스팔트에 부착한 RSC-4와 택코트 필름을 부착하여 부착강도를 평가했을때와 비슷한 경향을 나타냈다. 각각 1.241, 1.304로 택코트 필름과 보호필름을 사용한 쪽이 더 높게 나타났다. 이는 공사기간을 단축시킬 수 있을 뿐만 아니라 트래피커빌리티를 고려하였을 때 택코트 필름과 보호 필름을 사용하여 더 효율적으로 유지.보수를 할 수 있을 것으로 판단된다

PURPOSES:The purpose of this paper is to evaluate interface performance while using various tack coat materials for asphalt overlay.METHODS:The evaluation was conducted with tracking test, permeability, and interface bond strength. Tracking test was conducted using an image processing technique, to investigate the susceptibility of the tack coat materials. BBS and pull-off test were conducted to evaluate bond strength. The permeability test was conducted to evaluate the effect of tack coat materials.RESULTS :Results reveal that the trackless tack coat material demonstrates less tracking compared to other materials. Moreover, both BBS and pull-off tests can effectively evaluate the bond strength at the interface. RSC-4 was measured less bond strength. Moreover, tack coat prevents water penetration through the surface and aids the extension of the surface life of asphalt pavement.CONCLUSIONS :Trackless tack coat demonstrated a high and consistent bond strength performance. The tack coat types demonstrate marginally different performance as function of curing times. Field applicability was tested based on visual observation. Therefore, these should be considered when trackless tack coat is slightly enhanced the pavement performance based on limited this study results. Finally, it is necessary to allow reasonable time for the tack coat to completely cure.