한국 고속도로 포장은 1970년 경부고속도로 건설을 시작으로 많은 발전을 이루었으며, 최근 도로이용자에게 쾌적한 도로를 제공할 수 있는 배수성 아스팔트 포장에 대한 관심이 높아지고 있다. 본 연구에서는 한국 고속도로 배수성 아스팔트 구간에 대한 시공목적별, 신설과 유지보수 등을 구분하여 배수성 아스팔트 포장 적용현황을 분석하였다. 또한, 적용된 배수성 아스팔트 포장의 교통량을 조사 분석하였으며, 효율적인 교통량 그룹 선정 방법을 제시하였다. 고속도로에 적용된 배수성 아스팔트 포장의 전주기 평가를 위해 평가항 목을 제시하였다. 내구성평가 항목으로는 포장상태평가지수와 표면조도를 선정하였다. 기능성 평가 항목으로는 내부 공극 막힘여부를 확인할 수 있는 현장투수, 미끄럼저항지수, 포장노면과 타이어에서 발생하는 도로소음원 평가를 위한 도로소음을 선정하였다. 그리고 조사 항목들에 대한 배수성 아스팔트 포장의 전주기 평가를 통해 각각 조사 항목에 대한 정량적 분석평가를 수행하여 도로소음도 예 측식을 제안하였다.

이 연구에서는 해양폐기물인 해조류에서 추출된 알긴산을 혼입하여 모르타르의 압축강도 특성을 분석하였다. 알긴산은 해양폐기물 중 해조류의 성분 중 하나로 라텍스와 비슷한 성분을 띄고 있으며, 방수성 성질이 있어 포장용 콘크리트에 활용 시 콘크리트의 수명 을 연장하고 파손 방지에 도움이 된다. 따라서 이 연구에서는 기존에 널리 사용되고 있는 라텍스 콘크리트에 알긴산을 혼입한 라텍스 콘크리트 개발의 일환으로 알긴산 혼입 라텍스 모르타르의 역학적 특성에 대한 실험적 연구를 수행하였다. 실험결과, 알긴산 혼입량 증가에 따른 응결은 빨라지는 경향을 나타내었으며, 압축강도는 저하하는 경향을 나타내었다.

PURPOSES : The objective of this study is to analyze the significance of binder aging in a hot-mix asphalt (HMA) mixture in an insulated camber for a long duration for repair works, where the absolute viscosity level and service life reduction (SLR) are assessed based on the haul time, as well as to suggest a methodology for reducing the aging level. METHODS : Because the HMA mixture is stored in an insulated box carriage at high temperature for repair works, if the binder in the mix is severely oxidized, then the repaired pavement will not exhibit a long service life. Therefore, the 13-mm dense-graded HMA mix with PG64-22 was aged in an oven at 160 °C for 1, 2, 4 and 8 h to evaluate its aging level. Gel-permeation chromatography was performed on the mixture particle without binder recovery to measure the large-molecular size ratio, from which the estimated absolute viscosity (EAV) was computed using a best-fit regression model. The SLR values of aged and repaired mixes were estimated to determine the amount of deterioration in the mixes caused by severe aging. Hydrated lime (HL) was introduced into the mix at a ratio of 1.5 wt% of the total mix. The aging level and SLR were compared with those of the repaired mix without HL. RESULTS : The binder EAV of the HMA mix increases significantly with the mixture aging duration. In particular, the binder EAV level of a 4-h aged mix is similar to the asphalt viscosity level of a pavement with approximately 7 years of service life. The service life expressed based on the aging level is interpreted as the reduced service life of the aged mix, which is already oxidized before it is used. Meanwhile, the binder of an 8-h aged mix without HL aged significantly and its SLR is approximately 11 years. However, its aging level and SLR reduced significantly when HL. is incorporated. CONCLUSIONS : The binder aging level of the repaired mix increases significantly with its storage duration in a hot chamber for carriage. However, since the aging level decreases significantly by the incorporation of HL, the use of HL is highly recommended when preparing new mix for repair works to be performed in a hot-chamber for a long duration.

PURPOSES : The objective of this study is to evaluate the feasibility of applying properties of asphalt binder other than absolute viscosity (AV) to evaluate the rejuvenation level of the binder from reclaimed asphalt pavement (RAP) in recycled asphalt mixtures (RAMs). METHODS : The G*/sin and critical temperature (CT) for determining high performance grade by DSR, and the large molecular size (LMS) using gel-permeation chromatography (GPC) were measured simultaneously with the AV of two virgin asphalt binders (58–22 for RAM and 64–22 for normal mix) and recovered binders from a RAP and four RAMs. Based on mix design, 20%, 30%, 40%, and 50% recycled RAMs were prepared, and the deformation strength (SD) of the RAMs were measured. The AV, LMS, G*/sin , and CT were measured from the recovered binders from each RAM of the SD-tested specimens. Regression analyses were performed between the LMS and AV, G*/ sin and AV, and CT and AV to determine the correlation of each property with the AV. The feasibility of evaluating the rejuvenation level of the RMA binder using the three properties (LMS, G*/sin , and CT) was evaluated. Regression analysis was performed between SD and AV, and the feasibility of using SD instead of AV ≤ 5,000 poise (p) was analyzed to evaluate the rejuvenation level of the RAM. RESULTS : The AV, LMS, G*/sin , and CT of RAM binders increased with the recycling ratio. Mixes with recycle ratios of 20% and 30% satisfied the AV ≤ 5,000 p criterion, unlike mixes with higher recycle ratios. The regression analysis results showed that the R2 values between the LMS and AV, G*/sin and AV, and CT and AV exceeded 0.96. Since these regressions showed extremely high R2 values, it can be inferred that the estimation of binder rejuvenation level using the LMS, G*/sin and CT, i.e., instead of the AV criterion, is applicable. Because SD exhibits high correlation with the binder stiffness, and the regression between SD and AV indicated R2 > 0.98, SD can be applied instead of the AV for binder rejuvenation level estimation. The main advantage of using the LMS and SD is to estimate the binder rejuvenation level without recovering the binder from the mix. CONCLUSIONS : For the binder rejuvenation level estimation of recycled mixes, it is concluded that the LMS by GPC and G*/sin and CT by DSR, and SD can be applied instead of the AV criterion. However, since this study was performed using limited materials, further studies involving many other materials may be performed to generalize the current conclusion.

PURPOSES : This study evaluates the mechanical properties of high-viscosity polymer-modified asphalt binders using PG and MSCR tests. METHODS : Using the Superpave asphalt binder performance grade (PG) and multi-stress creep recovery (MSCR) test methods, the linear (dynamic shear modulus, stiffness, and viscosity) and non-linear properties — i.e., non-recoverable compliance (Jnr) and recoverable shear strain % recovery — of 16 different types (SBS, SIS, PE, PP) of polymer-modified asphalt binders were assessed. RESULTS : Based on the viscosity testing results. Most PG 82 binders did not meet the criterion of 3 Pa ·s. This indicates that they need to increase the mixing and compaction temperatures to reduce the high viscosity. The MSCR % Jnr results demonstrated that PG 76, PG 82–22, and PG 82-28/34 binders were below 1.0, 0.5, and 0.2, respectively. In addition, the MSCR % recovery results showed that PG 76, PG82-22, and PG82-28/34 were above 35 %, 55 %, and 80 %, respectively. CONCLUSIONS : It was found that the % Jnr decreased with an increase in the high-temperature PG of the asphalt binder, whereas the % recovery increased as the low-temperature PG of the binder increased.

PURPOSES : This study uses deep learning image classification models and vehicle-mounted cameras to detect types of pavement distress — such as potholes, spalling, punch-outs, and patching damage — which require urgent maintenance. METHODS : For the automatic detection of pavement distress, the optimal mount location on a vehicle for a regular action camera was first determined. Using the orthogonal projection of obliquely captured surface images, morphological operations, and multi-blob image processing, candidate distressed pavement images were extracted from road surface images of a 16,036 km in-lane distance. Next, the distressed pavement images classified by experts were trained and tested for evaluation by three deep learning convolutional neural network (CNN) models: GoogLeNet, AlexNet, and VGGNet. The CNN models were image classification tools used to identify and extract the combined features of the target images via deep layers. Here, a data augmentation technique was applied to produce big distress data for training. Third, the dimensions of the detected distressed pavement patches were computed to estimate the quantity of repair materials needed. RESULTS : It was found that installing cameras 1.8 m above the ground on the exterior rear of the vehicle could provide clear pavement surface images with a resolution of 1 cm per pixel. The sensitivity analysis results of the trained GoogLeNet, AlexNet, and VGGNet models were 93 %, 86 %, and 72 %, respectively, compared to 62.7 % for the dimensional computation. Following readjustment of the image categories in the GoogLeNet model, distress detection sensitivity increased to 94.6 %. CONCLUSIONS : These findings support urgent maintenance by sending the detected distressed pavement images with the dimensions of the distressed patches and GPS coordinates to local maintenance offices in real-time.

본 연구에서는 해양수산부 연안침식 실태조사에서 운영 중인 해운대 해수욕장 비디오 모니터링 시스템을 이용하여 연안정비 사업 실시 이후의 백사장 면적변화를 분석하였다. 해운대 해수욕장은 연안정비사업을 통한 대규모 양빈이후 계절변동 특성과 함께 해빈 안정화 과정을 거치면서 잘 유지되었으나, 최근 2년간 복수의 태풍 내습에 의하여 해운대 해수욕장의 계절변동특성 및 해빈안정화 양상은 균형을 상실하였으며, 급격한 침식이 발생하였다. 특히, 2018년 태풍 솔릭, 콩레이에 의해 침식된 백사장은 계절변동에 의한 겨울철 해빈면적을 회복하지 못하였으며, 2019년에 내습한 다수의 태풍들로 인하여 해빈면적이 전년 대비 9.5 %(12,607 m2) 감소하였다. 해운대 해빈 전면에서 관측된 파랑자료와 해빈면적자료를 분석한 결과, 계절에 따른 입사파향에 따라 백사장의 서측, 중앙부, 동측의 침퇴적 경 향이 뚜렷이 나타났다. 향후에는 계절변동특성의 둔화와 지속적인 침식경향이 나타나는 원인을 파악하기 위해 잠제 시설물의 마루높이, 기능유지 여부 및 잠제 외부로의 모래유출추적 등 보다 정밀한 모니터링이 필요하다.