PURPOSES : This research assesses the influence of emulsified asphalt on vegetation growth by examining parameters such as moisture content, temperature, pH, electrical conductivity, and analyzing the extent of green coverage using image analysis. METHODS : Within this study, sensors were employed to measure the growth environment of vegetation treated with emulsified asphalt. Furthermore, the analysis of the greening rate through image analysis has been incorporated. RESULTS : Research indicates that emulsified asphalt effectively secures seeds to surfaces and maintains moisture content for an extended period. However, the excessive utilization of emulsified asphalt has been observed to reduce germination and greening rates. CONCLUSIONS : The application of an optimal emulsified asphalt content is presumed to promote vegetation growth. To establish objective, it is imperative to conduct comprehensive research on its long-term structural effects regarding growth, greening rate, and slope when integrated with emulsified asphalt.

PURPOSES : The purpose of this study is to analyze the effect of ions in emulsion asphalt on recycling cold asphalt concrete and suggest the possibility of using anionic and nonionic emulsion asphalt. METHODS : In this study, indirect tensile strength, toughness, tensile strength ratio, and dynamic immersion tests were conducted to determine the effects of cation, anion, and non-ion emulsified asphalt on the cold recycled asphalt mixture. Crack resistance was evaluated through indirect tensile strength and toughness tests and the tensile strength ratio and dynamic immersion test were evaluated through tensile strength ratio and dynamic water immersion test. RESULTS : Indirect tensile strength and toughness measurement results demonstrated that the mixture using anion and non-ion emulsified asphalt tended to be higher than that using cation emulsified asphalt; this is due to the high content of reclaimed asphalt pavement with a cationic or ionic surface, which is related to the use of cation-emulsified asphalt in the mixture and has shown a low strength tendency. The tensile strength ratio measurement demonstrated that the mixture using non-ion emulsified asphalt tended to be approximately 15 % higher than that of the anion mixture. This demonstrated that the chemical additive used in the mixture showed a complete hydration reaction with the distribution to the mixture. The dynamic immersion test indicates that the aggregate film rate of asphalt is highly influenced by the surface electric charge of the new aggregate while the ionicity effect appears to be insignificant, at 75 - 85 %, when circular aggregates are used. CONCLUSIONS : High reclaimed asphalt pavement content in cold recycled asphalt mixture, as well as non-ion and anionic emulsified asphalt, is advantageous, reducing cracking and improving moisture resistance. It is believed that anions and non-ions may be better utilized than applying the existing criteria to the cold temperature recycled asphalt mixture with high reclaimed asphalt pavement content. In addition, if the scope of the emulsified asphalt is expanded, various additives can be used, which will require analysis of materials, such as fertilizers and additives.

PURPOSES : The purpose of this study is to examine the manufacturing method for emulsified asphalt and its bond performance by analyzing the properties of the emulsifier used to produce cold recycled asphalt mixtures. METHODS: In this study, four types of slow-setting cationic emulsifiers, a microsurfacing emulsifier, and six types of nonionic emulsifiers were used to manufacture emulsified asphalt. Because each emulsifier requires its own unique effective dose to provide the best performance, the optimum asphalt content for each effective dose was determined. Then, the optimum asphalt content for the emulsified asphalt mixture was determined by the tests to check its basic physical properties. By using the determined optimum content, asphalt mixtures were manufactured and dynamic immersion and tensile strength tests were conducted on the mixtures to analyze the influence of the emulsifier on the physical properties of the mixtures. RESULTS : The dynamic immersion test results showed a coating ratio of 54-85%, which is considerably higher than that of using ordinary straight asphalt. The tensile strength test yielded noncompliant values less than 0.4 N/mm, which is the standard requirement for dry indirect tensile strength. The correlation analysis between the dynamic immersion and tensile strength ratio tests showed very high correlation of 0.78. The correlation between the emulsifier content and water resistance performance was low, between -0.55 and -0.24. CONCLUSIONS : While the storage stability improves with increasing emulsifier, the effectiveness proportional to the increase is weaker as the emulsifier increases. The performance testing of asphalt residues before and after manufacturing the emulsified asphalt showed no significant change. It is proved that the emulsified asphalt maintains high coating resistance according to the dynamic immersion test results. In addition, according to the results of tensile strength ratio, cold recycled asphalt mixtures manufactured by the materials normally and commercially used are not compliant with the national standard specification; thus, additional effective materials will be needed for quality compliance. In conclusion, it is evident that the dynamic immersion and tensile strength ratio tests have good correlation, but the quantity of emulsifiers used is not related to the level of moisture resistance.

PURPOSES: The purpose of this study is to evaluate the mechanical properties of a cold-recycling asphalt mixture used as a base layer and to determine the optimum emulsified-asphalt content for ensuring the mixture’s performance. METHODS: The physical properties (storage stability, mixability, and workability) of three types of asphalt emulsion (CMS-1h, CSS-1h, and CSS-1hp) were evaluated using the rotational viscosity test. Asphalt emulsion residues, prepared according to the ASTM D 7497-09 standard, were evaluated for their rheological properties, including the G*/sinδand the dynamic shear modulus (|G*|). In addition, the Marshall stability, indirect tensile strength, and tensile-strength ratio (TSR) were evaluated for the cold-recycling asphalt mixtures fabricated according to the type and contents of the emulsified asphalt. RESULTS: The CSS-1hp was found to be superior to the other two types in terms of storage stability, mixability, and workability, and its G*/sinδ value at high temperatures was higher than that of the other two types. From the dynamic shear modulus test, the CSS-1hp was also found to be superior to the other two types, with respect to low-temperature cracking and rutting resistance. The mixture test indicated that the indirect tensile strength and TSR increased with the increasing emulsified-asphalt content. However, the mixtures with one-percent emulsified-asphalt content did not meet the national specification in terms of the aggregate coverage (over 50%) and the indirect tensile strength (more than 0.4 MPa). CONCLUSIONS : The emulsified-asphalt performance varied greatly, depending on the type of base material and modifying additives; therefore, it is considered that this will have a great effect on the performance of the cold-recycling asphalt pavement. As the emulsified-asphalt content increased, the strength change was significant. Therefore, it is desirable to apply the strength properties as a factor for determining the optimum emulsified-asphalt content in the mix design. The 1% emulsified-asphalt content did not satisfy the strength and aggregate coverage criteria suggested by national standards. Therefore, the minimum emulsified-asphalt content should be specified to secure the performance.

비가열식 상온 도로포장 재활용 공법인 상온 현장 재활용 공법(CIR), 상온 플랜트 재활용 공법(CCPR), 상온 전체 포장층 재활용 공법(FDR)들은 경제적으로 시공 비용이 저렴하고 공사기간을 단축시키며 환경오염 영향을 적게 미치는 장점이 있다. 상온 재활용 공법에 사용되는 아스팔트 바인더는 크게 유화아스팔트(emulsified asphalt)와 폼드 아스팔트(foamed asphalt)가 적용되며, 이들은 재생 아스팔트 혼합물의 재생첨가제 또는 안정제로서의 기능을 하기도 한다. 유화아스팔트는 물속에 아스팔트 바인더 입자(1-3μm)가 계면활성제(surfactant)에 의해 상분리 현상을 일으키지 않고 분산 상태를 유지하고 있는 액체 상태의 아스팔트이기 때문에 상온에서 별도의 가열 없이 편리하게 사용할 수 있다. 하지만 상온 재활용 아스팔트 콘크리트에 대한 공학적 구조 해석을 위한 정량적 데이터가 부족하여 공학적 공용성 분석이 이루어지지 못해 널리 활성화 되는데 한계점을 가지고 있다. 본 연구는 상온 재활용 아스팔트 콘크리트용 개질 유화아스팔트의 개발을 목적으로 개질재(천연고무, 합성고무 등)에 의한 유화아스팔트 바인더의 정량적 물성 성능 평가를 위하여 기초적 실험평가를 실시하였다. 아스팔트 바인더(AP-3)를 개질 첨가제인 천연고무, 합성고무 A와 B를 각각 3% 첨가하여 개질시키고 유화 과정을 시켜 개질 유화아스팔트를 제조하였다. 이렇게 제조된 개질 유화아스팔트의 증발잔류물(평균 61%)에 대해 침입도와 연화점 시험을 실시하였다. 시험결과 천연고무와 합성고무 B로 개질 유화아스팔트의 연화점이 66℃과 67℃로 합성고무 A(51℃)보다 높게 나타났고, 침입도는 천연고무로 개질된 유화아스팔트가 49로 합성고무(A) 66와 합성고무(B) 74로 측정되었다. 천연고무로 개질된 유화아스팔트의 물성 성능이 가장 우수하였고 혼합성 및 저장안전성도 양호하였다. 천연고무, 합성고무 A와 B를 적용한 개질 유화아스팔트의 물성 성능평가를 통해 기초적 자료를 확보하였고, 향후 상온 재활용 아스팔트 콘크리트 혼합물에 대한 공용성능 평가를 통해 공학적 공용성 분석을 진행할 예정이다.

최근 우리나라의 도로포장은 환경의 영향, 교통량의 증가 및 차량의 중량화 등 여러 요인에 의해 설계 수명에 이르지 못하고 조기에 노후화되어 이를 위한 유지보수가 빈번히 시행되고 있다. 유지보수로 인해 발생하는 폐아스팔트 콘크리트는 주요 건설폐기물로써 이에 대한 처리는 중대한 사회적 문제로 나타나고 있으며, 유지보수 시 공사구간 통제로 인한 차량지체현상으로 사용자비용이 발생하고 있다. 본 연구에서 는 이러한 현실적 문제를 극복하고자 폐아스팔트 콘크리트를 순환골재로 이용함과 동시에 개질 유화아스 팔트를 적용한 상온 긴급보수재료 개발에 대한 실험적 분석을 수행하였다. 개질 유화 아스팔트를 사용하여 상온에서 마샬 안정도 시험을 실시한 결과 순환골재(RAP)를 사용했을 때 신규골재(VA)를 사용했을 때 보다 1-2%의 바인더 절감 효과가 나타났으며, 성능이 더 우수함을 확인 할 수 있었다. 또한, 습윤 마모 시험을 통하여 순환골재(RAP)와 신규골재(VA)를 비교한 결과 순환골재 (RAP)의 마모저항성이 더 우수함을 확인할 수 있었다.

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 : The objective of this study is to evaluate the curing and adhesive behavior of asphalt emulsions including polymer-modified emulsions for chip seals and fog seals. METHODS : For the laboratory testing, the evaporation test, the bitumen bond strength (BBS) test, and the Vialit test are used. Also, the rolling ball test and the damping test are employed to evaluate the curing properties of the fog seal emulsions. In order to conduct all the tests in controled condition, all test procedures are performed in the environmental chamber. The CRS-2L and the SBS CRS-2P emulsions are used as a polymer-modified emulsion, and then unmodified emulsion, the CRS-2, is compared for the evaluation of chip seal performance. For the fog seal performance evaluation, two types of polymer-modified emulsions (FPME-1 and FPME-2) and one of unmodified emulsion, the CSS-1H, are employed. All the tests are performed at different curing times and temperatures. RESULTS AND CONCLUSIONS : Overall, PMEs show better curing and adhesive behavior than non-PMEs regardless of treatments types. Especially, the curing and adhesive behavior of PMEs is much better than non-PMEs before 120 minutes of curing time. Since all the test results indicate that after 120 minutes of curing time the curing adhesive behavior of emulsions, the early curing time, i.e., 120 minutes, plays an important role in the performance of chip seals and fog seals.

PURPOSES : The objective of this study is to evaluate the bond strength of asphalt emulsions including polymer-modified emulsions for chip seals and fog seals using the bitumen bond strength (BBS) test. METHODS : For the laboratory testing, the Pneumatic Adhesion tensile Testing Instrument(PATTI) device is used to measure the bond strength between the asphalt emulsion and aggregate substrate based on the AASHTO TP-91. In order to conduct all the tests in controled condition, all test procedures are performed in the environmental chamber. The CRS-2L and the SBS CRS-2P emulsions are used as a polymermodified emulsion, and then unmodified emulsion, the CRS-2, is compared for the evaluation of chip seal performance. For the fog seal performance evaluation, two types of polymer-modified emulsions and one of unmodified emulsion, the CSS-1H, are employed. For chip seal study, the BBS tests are performed at 30, 60, 120, and 240 minutes of curing times with curing and testing temperatures of 15℃, 25℃, and 35℃. The fog seal tests are conducted at 30, 60, 90, 120, 180 minutes, and 24 hours with curing and testing temperatures of 25℃, 30℃, and 35℃. RESULTS AND CONCLUSIONS : Overall, chip seal emulsions and fog seal emulsions show the similar bond strength trend. At the same testing condition, polymer-modified emulsions show better bond strength than unmodified emulsions. Also, there is no significant difference between polymer-modified emulsions. One of important findings is that the most bond strength reaches their final bond strength within one hour of curing time. Therefore, the early curing time plays a vital role in the performance of chip seals and fog seals.

현재 아스팔트 도로 분야에서 신규건설 수요는 점차 감소되고 있으며, 기존 공용중인 도로의 사용기간 이 증가함에 따라 도로포장의 파손이 증가하기 때문에 도로의 재포장 및 유지보수의 수요가 증가하는 실 정이다. 기존 도로의 유지보수 적용 시 교통통제가 야기하는 도로 사용자의 불편 및 경제적 손실을 고려 해야하며, 또한 유지보수를 위한 비용을 시공 후 공용성과 비교하여 고려해야 한다. 미국 주 교통국에서 는 이러한 문제점들을 고려하여 현장 상황에 적합한 유지보수 공법을 선정하여 적용하고 있으며, 칩실과 포그실로 대표되는 아스팔트 표면처리공법(Asphalt Surface Treatments)의 사용이 증가하고 있다. 칩실 은 여러 유지보수 공법 중 경제적이고 효과적인 공법으로 시공 후 3~4시간 후에 교통을 개방한다. 때문 에 칩실의 초기 양생시간(3~4시간)이 칩실의 충분한 공용성 발현에 중요한 역할을 한다. 본 연구에서는 칩실의 초기 공용성을 평가하기 위하여 CRS-2 일반 유화아스팔트와 5 종의 폴리머 개질 유화아스팔트 (PME-A, -B, -C, -D, -E)를 사용하여 칩실 시편을 제작한 후 증발 시험(Evaporation Test), 점착력 시험(Bitumen Bond Strength, BBS Test), Vialit Test, MMLS3 골재 탈리 시험을 통하여 칩실의 초기 골재 부착력 특성을 평가하였다. 그림 1에서 Vialit Test의 골재 탈리 결과와 BBS Test로 얻어지는 각 유 화아스팔트의 점착력을 비교하였고, 미국 알래스카 주 교통국에서 칩실의 공용성 판단 요소로 제시한 10% 골재 탈리율 기준을 MMLS3 시험 결과와 Vialit Test 시험결과 사이의 관계식을 통하여 13%로 수정 하여 실험 결과에 적용하여 평가하였다