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 : 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: The purpose of this study was to develop an urgent road-repair system and perform a field applicability test, as well as discover the optimum mix design for machine applications compared to the optimum mix design for lab applications. METHODS: According to reviews of the patent and developed equipment, self-propelled and mix-in-place equipment types are suitable for urgent pavement repair, e.g., potholes and cracks. The machine-application mix design was revised based on the optimum lab-test mix design, and the field application of a spray-injection system was performed on the job site. The mixture from the machine application and lab application was subjected to a wet-track abrasion test and a wheel-tracking test to calibrate the machine application. RESULTS and CONCLUSIONS : This study showed that the binder content could differ for the lab application and the machine application in the same setting. Based on the wet-track abrasion test result, the binder contents of the machine application exceeded the binder contents of the lab application by 1-1.5% on the same setting value. Moreover, the maximum dynamic stability value for the machine application showed 1% lower binder contents than the maximum lab-application value. Collectively, the results of the two different tests showed that the different sizes and operating methods of the machine and lab applications could affect the mix designs. Further studies will be performed to verify the bonding strength and monitor the field application.

PURPOSES: The main distress of asphalt pavements in monsoon climate regions are caused by water damage and plastic deformation due to repeated rain season and increased heavy vehicle traffic volume. In this study, the mechanical properties of polymer-modified warm mix asphalt (PWMA) materials are evaluated to use in monsoon climate regions such as Indonesia. METHODS: Comprehensive laboratory tests are conducted to evaluate moisture resistance and permanent deformation resistance for three different asphalt mixtures such as the Indonesian conventional hot-mix asphalt (HMA) mixture, the polymer-modified asphalt mixture, and the polymer-modified warm mix asphalt (PWMA) mixture. Dynamic immersion test and indirect tensile strength ratio test are performed to evaluate moisture resistance. The wheel tracking test is performed to evaluate rutting resistance. Additionally, the Hamburg wheel tracking test is performed to evaluate rutting and moisture resistances simultaneously. RESULTS: The dynamic immersion test results indicate that the PWMA mixture shows the highest resistance to moisture. The indirect tensile strength ratio test indicates that TSR values of PWMA mixture, Indonesian PMA mixture, and Indonesian HMA mixture show 87.2%, 84.1%, and 67.9%, respectively. The wheel tracking test results indicate that the PWMA mixture is found to be more resistant to plastic deformation than the Indonesian PMA. The dynamic stability values are 2,739 times/mm and 3,150 times/mm, respectively. Moreover, the Hamburg wheel tracking test results indicate that PWMA mixture is more resistant to plastic deformation than Indonesian PMA and HMA mixtures. CONCLUSIONS: Based on limited laboratory test results, it is concluded that rutting resistance and moisture susceptibility of the PWMA mixture is superior to Indonesian HMA and Indonesian PMA mixtures. It is postulated that PWMA mixture would be suitable for climate and traffic conditions in Indonesia.

PURPOSES :The purpose of this study was to determine the optimum mix design of the content of 100 % reclaimed asphalt pavement (RAP) for spray injection application with different binder types.METHODS:Literature review revealed that spray injection method is the one of the efficient and economical methods for repairing a small defective area on an asphalt pavement. The Rapid-Setting Polymer modified asphalt mixtures using two types of rapid setting polymers-asphalt emulsion and a quick setting polymer asphalt emulsion-were subjected to the following tests to determine optimum mix designs and for performance comparison: 1) Marshall stability test, 2) Retained stability test, 3) Wet track abrasion test, and 4) Dynamic stability test.RESULTS AND CONCLUSIONS :Type A, B, and C emulsions were tested with different mix designs using RAP aggregates, to compare the performances and determine the optimum mix design. Performance of mixtures with Type A emulsion exceeded that of mixtures with Type B and C emulsion in all aspects. In particular, Type A binder demonstrated the highest performance for WTAT at low temperature. It demonstrated the practicality of using Type A mixture during the cold season. Furthers studies are to be performed to verify the optimum mix design for machine application. Differences in optimum mix designs for machine application and lab application will be corrected through field tests.

PURPOSES: The objective of this study was to determine the optimum ratio of mix design, for a reclaimed asphalt pavement (RAP) content of 100%, for spray injection application. METHODS: A literature review revealed that spray injection is an efficient and cost-effective application for fixing small defective regions of an asphalt pavement. Rapid-setting polymer-modified asphalt mixtures prepared from two types of rapid-setting polymer asphalt emulsion were subjected to Marshall stability and wet track abrasion tests, in order to identify the optimum mix designs. RESULTS and CONCLUSIONS : Different mix designs of type A and type B emulsions were prepared using RAP and virgin aggregates, in order to compare the performance and determine the optimum mix design. The performance of mixtures prepared with RAP was superior to that of mixtures containing virgin aggregates. Moreover, for optimum ratio of the design, the binder content prepared from RAP was set to 1~2% lower than that consisting of virgin aggregates. Compared to their Type A counterparts, type B mixtures consisting of a reactive emulsion performed better in the Marshall stability and wet track abrasion tests. The initial results confirmed the advantages associated with using RAP for spray injection applications. Further studies will be performed to verify the difference in the optimum mix design and performance obtained in the lab-scale test and tests conducted at the job site by using the spray injection machine.

PURPOSES: The objectives of this study were to develop a new polymer-modified emulsion for application to tack coats and to evaluate its properties by comparing it with other types of asphalt emulsions, with the goal of providing an enhanced tack coat material for use in construction. METHODS: Modified asphalt binders were developed from using SBS and SBR latex in the laboratory, and their fundamental properties, such as their penetration index and PG grade, were evaluated. Based on the properties, a new tack coat material was developed. To evaluate the newly developed asphalt emulsion, the bonding strength between the two layers of HMA was measured by applying a uniaxial tensile test and shear test. For the tests, a total of four different conditions were applied to the specimens, including the developed asphalt emulsion, latex modified asphalt emulsion, conventional asphalt emulsion, and non-tack coating. RESULTSAND CONCLUSIONS: Overall, the developed asphalt emulsion exhibits the best bonding strength behavior among all of the three types. Also, the two types of polymer-modified emulsions were found to be better for application for use as a tack coat than a conventional emulsion. Especially, at a high temperature (50℃), the conventional asphalt emulsion no longer acts as a tack coating material. Therefore, the polymer-modified emulsion should be considered for application to tack coat construction during the summer.

PURPOSES : The purpose of this study was to evaluate the performance of rapid-setting polymer-modified asphalt mixtures with a high reclaimed asphalt pavement (RAP) content. METHODS: A literature review revealed that emulsified asphalt is actively used for cold-recycled pavement. First, two types of rapid-setting polymer-modified asphalt emulsion were prepared for application to high-RAP material with no virgin material content. The quick-setting polymer-modified asphalt mixtures using two types of rapid-setting polymer-modified asphalt emulsion were subjected to the following tests: 1) Marshall stability test, 2) water immersion stability test and 3) indirect tensile strength ratio test. RESULTS AND CONCLUSIONS : Additional re-calibration of the RAP was needed for laboratory verification because the results of analyzing RAP aggregates, which were collected from different job sites, did not deviate from the normal range. The Marshall stability of each type of binder under dry conditions was good. However, the Type B mixtures with bio-additives performed better in the water immersion stability test. Moreover, the overall results of the indirect tensile strength test of RAP mixtures with Type B emulsions exceeded 0.7. Further research, consisting of lab testing and on-site application, will be performed to verify the possibility of using RAP for minimizing the closing of roadways.

PURPOSES: SUPERPAVE binder grade tests including Multiple Stress Creep and Recovery(MSCR) test are applied to evaluate rheological properties of four polymer modified binders. METHODS: To evaluate grade of four modified binders, PG testing protocols, such as DSR, BBR and MSCR are employed. RESULTS: It is observed that MSCR test shows different performance grades especially on modified binders. Both DMP and EG binder show similar high temperature performance to SBS 5% modified binder. CONCLUSIONS: Binder Grading system in Korea need to be reviewed to properly reflect the performnace of modified binders. The binders modified with DMP and EG can be possible alternatives SBS 5% modified binder considering its performance and cost.

본 연구에서는 국내 LTPP 구간에서 수행된 FWD 시험의 결과를 바탕으로 섬유보강, 폴리머 개질, 일반 아스팔트 포장의 구조적 성능을 비교 평가하였다. FWD 시험 결과, 표층 하단부의 인장변형량이 섬유보강 아스팔트는 29%, 폴리머 개질 아스팔트는 21% 저감되는 것을 확인하였다. 또한 FWD 처짐량을 역산하여 각 층의 탄성계수를 추정한 후 이를 바탕으로 AASHTO 설계방법, 구조적 해석 방법 및 생애주기비용분석을 통해 섬유보강 및 폴리머 개질 아스팔트 포장의 비용 효과를 분석하였다. 분석 결과, 섬유보강은 약 5cm, 폴리머 개질은 약 3cm의 아스팔트 층 두께 감소 효과를 보여주었다. 그러나 섬유보강 및 폴리머 개질 아스팔트의 고가격으로 인하여 전체 시공재료비는 일반 아스팔트 포장에 비해 상승하는 결과를 보여주었다. 생애주기비용 결과는 초기 공사비는 섬유보강 및 폴리머 개질 아스팔트 포장이 높지만, 유지관리비용 및 사용자비용은 감소하는 것으로 나타났다.

Low-density polyethylene (LDPE)와 Styrene-butadiene-styrene (SBS)를 넣은 개질 아스팔트 혼합물은 바인더에 중량 비로 3~6% 첨가하여 여러 가지 특성을 획기적으로 향상시킨 아스팔트 재료이다. 아스팔트 재료의 개질목적은 일반 혼합물의 균 열저항과 소성 변형과 같은 전형적인 약점을 향상시키기 위해서이다. 이 재료들은 많은 장점들을 가지고 있으며 플랜트 적용이 간편하고 현장적용성이 우수한 특정을 가지고 있다. 여러 해 동안의 경험을 통해 습식 개질 아스팔트와 건식 아스팔트 혼합물이 현장에서 실용화할 수 있게 발전되었다. 본 연구에서는 이를 종합적으로 평가하여 그 장단점을 일반 아스팔트 혼합물과 비교 평가하여 LDPE, SBS 개질 아스팔트 혼합물의 특성을 체계적으로 밝히는 것을 본 연구의 목적으로 한다.

본 연구는 동절기에 많이 발생하는 포장의 저온균열에 대한 폴리머 개질 아스팔트 혼합물의 저항 특성을 알아보기 위하여 수행하였다. 저온에서의 간접인장강도를 측정 분석한 결과 혼합물들이 -10°C ~ -20°C의 저온 대에서 최대 인장강도를 나타냈다. 최대 인장강도를 보이는 온도 이하에서는 시차열 응력이 인장강도 이상으로 발생하여 내부에 손상이 발생하기 때문에 나타나는 인장강도 저하현상을 ITS 시험으로 증명하여 보였다. 저온의 시험 결과는 폴리머 개질 아스팔트 혼합물이 일반 아스팔트 혼합물에 비하여 보다 낮은 온도에서까지도 강도가 높게 나타나 폴리머 개질에 따른 효과를 보였으며, 바인더가 저온균열에 대한 저항에 큰 영향을 미치는 것으로 나타났다. 따라서 추운 지역에서는 저온균열을 예방하기 위하여 폴리머 개질 아스팔트의 사용이 추천된다.

본 연구는 동절기에 많이 발생하는 포장의 저온균열에 대한 폴리머 개질 아스팔트 혼합물의 저항 특성을 알아보기 위하여 수행하였다. 저온에서의 간접인장강도를 측정 분석한 결과 혼합물들이 -10℃의 저온 대에서 최대 인장강도를 나타냈다. 최대 인장강도를 보이는 온도 이하에서는 시차열 응력이 인장강도 이상으로 발생하여 내부에 손상이 발생하기 때문에 나타나는 인장강도 저하현상을 ITS 시험으로 증명하여 보였다. 저온의 시험 결과는 폴리머 개질 아스팔트 혼합물이 일반 아스팔트 혼합물에 비하여 보다 낮은 온도에서까지도 강도가 높게 나타나 폴리머 개질에 따른 효과를 보였으며, 바인더가 저온균열에 대한 저항에 큰 영향을 미치는 것으로 나타났다. 따라서 추운 지역에서는 저온균열을 예방하기 위하여 폴리머 개질 아스팔트의 사용이 추천된다.