• Journal of Adhesion and Interface
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• v.10 no.4
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• pp.182-190
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• 2009

In this work, effect of antistrip additives to reduce moisture damage of asphalt mixture were studied. Asphalt antistripping agents were prepared by condensation of formaldehyde with tetraethylene pentamine (TEPA), triethylenetetramine (TETA) and bis(hexamethylene)-triamine (BHMT), respectively. And also the metal type antistripping agent was prepatred by neutralization of stearic acid or palmitic acid with metal hydroxide. Mechanical characteristics of the asphalt mixture added antistripping agent were evaluated with Marshall stability, submerging residuals and coating rate. It was found that antistripping agent prepared in this study reduced moisture damages of asphalt mixtures. In particular, asphalt mixtures added BHMT and C/S (Calcium stearate hydroxide) antistripping agent showed highest submerging and coating rate. Because BHMT and C/S type antistripping agent was to improve bonding between asphalt and aggregate owing to increase of amine concentration and role of metal surfactant.

• International Journal of Highway Engineering
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• v.3 no.4 s.10
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• pp.105-116
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• 2001

This study was performed to evaluate the characteristics of waste foundry sand (WFS) and the asphalt mixture made of a foundry waste sand. To estimate the applicability of WFS, chemical and physical properties were measured by XRF(X-ray fluorescent), and SEM(Scanning electronic microfilm). To improve the stripping resistance of WFS asphalt mixture, anti-stripping agents (a hydrated lime and a liquid anti-stripping agent) were used. To improve tensile properties and durability of WFS asphalt concrete mixture, LDPE(low-density polyethylene) was used as an asphalt modifier Marshall mix design, indirect tensile strength, tensile strength ratio(TSR) after freezing and thawing, moisture susceptibility and wheel tracking tests were carried out to evaluate performance of WFS asphalt concrete. Comparing with conventional asphalt concrete, WFS asphalt concretes showed similar or the better qualify in mechanical properties, and satisfied all specification limits. Therefore, it Is concluded that waste foundry sand can be recycled as an asphalt pavement material.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.319-325
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• 2018

Pot-holes are steadily increasing due to abnormal climate such as heavy rainfall and frequent snowfall. Pot-hole related to traffic accidents cause injuries, car damage and distress of road facilities. To reduce pot-holes, the use of an anti-stripping agent is mandatorily recommended to asphalt concrete mixture. Hydrated lime is commonly used as anti-stripping agent due to the convenience and economics. Byproduct ash from circulating fluidized bed boiler was reviewed as an anti stripping agent. According to the test results, the byproduct ash is satisfied with TSR specification using 1% to 3% by weight of the asphalt mixture. The byproduct ash was examined under various condition changes of aggregate and asphalt concrete mixture considering quality movement. According to the results, using the byproduct ash was measured average 0.87 of TSR and coverage rates of 60% after rolling bottle test. Test results also revealed that the byproduct ash showed stable performance. Using the byproduct ash to decrease pot-hole in asphalt concrete pavement is suitable for demonstrating stable performance as anti-stripping agent.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.4
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• pp.523-530
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• 2019

Pavement distress and traffic accidents are caused by pot-hole. In addition, direct and indirect damages of road users are increasing, such as loss of life due to personal injury and damage to vehicles. Generally, the asphalt concrete pavements are continuously aging from the production process to the terminal performance period. Aging causes stripping due to cracks and moisture penetration and weakening the pavement structure to induce pot-hole. In this study, adhesion performance and moisture sensitivity were evaluated according to aging degree in order to investigate the effect of aging on asphalt pavement. As a result of the study, the viscosity of the asphalt binder was increased with aging and the bond strength of the aged was increased 2~3 times than that of the unaged. The results of accelerated aging test showed an increases in indirect tensile strength and the increase in the TSR (Tensile Strength Ratio) by 4.2~8.9 %. As a result, it is noted that the anti-stripping and adhesion performances of the aged asphalt concrete are improved compared to the unaged one under the aging conditions of asphalt binder coated on aggregates.

• International Journal of Highway Engineering
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• v.6 no.1 s.19
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• pp.13-23
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• 2004

This paper presents the results of a study that was performed to evaluate structural behaviors and related distress of asphalt pavements on concrete bridge deck based on the visual inspection and 3-dimensional finite element analysis. As a result, three most failure types were found such as permanent deformation, potholes, and fatigue crackings. In addition, the failure mechanisms of different types of concrete bridge deck were investigated. An increase in fatigue of asphalt pavements on concrete bridge deck was observed and confirmed by the results from the visual inspections. In consequence, the aging and stripping of asphalt surfacing materials are relatively dominant factors on fatigue rather than traffic loadings.

• International Journal of Highway Engineering
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• v.9 no.4
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• pp.149-158
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• 2007

Evaluation of the asphalt mixture modified with crumb rubber modifier(CRM) was performed to estimate possibility of using it as a paying material. OACs(optimum asphalt content) of CRM modified asphalt mixtures by dry process and wet process were determined by Marshall mix design and Wheel tracking test and moisture susceptibility test by freezing and thawing were carried out with CRM modified asphalt mixtures at OACs. The results from these tests, resistance of permanent deformation of CRM modified asphalt mixtures were superior to one of AP-5 while showing very low resistance of moisture sensitivity by freezing and thawing. This means that CRM modified asphalt mixtures are very sensitive to freezing and thawing. However, CRM modified asphalt mixture with anti-stripping material showed high improvement to resistance of moisture susceptibility by freezing and thawing. Therefore, it is recommended that when CRM mixtures were used in domestic, CRM modified asphalt mixtures should be with prevention against freezing and thawing resistance by moisture susceptibility.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.13-25
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• 2007

Viscosity, adhesion and cohesion of asphalt binder are very important characteristics in asphalt pavement. However, these characteristics can cause some problems such as inaccurate amount of asphalt mixture, reduction of asphalt content and loss of workability during asphalt pavement construction. Asphalt release agent has been used to solve these problems. Diesel oil and vegetable oil are generally used as an asphalt release agent in Korea. However, these agents have been criticized from environmental and binder integrity reasons. Therefore, this study evaluated the characteristics of asphalt release agents including diesel oil, vegetable oil and two emulsion type oils. From the study, it was found that the diesel oil resolved the binder within ten minutes and vegetable oil stripped the binder from mixture within one hour after contacting with asphalt mixture. And also, from the test for estimating the application cycle of asphalt release agent, it appears that diesel oil and vegetable oil should be applied to construction equipments every time in their uses. However, diesel oil and vegetable oil showed a good performance as a lubricant for detaching the asphalt mixtures from the truck bed.

• 한국도로학회지:도로
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• v.11 no.2
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• pp.26-33
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• 2009

본 특집기사는 미국 NCAT(National Center for Asphalt Technology)에서 실험한 보고서(Hurley 및 Prowell, Evaluation of Sasobit for Use in Warm Asphalt, 2005)를 정리한 것으로 아스팔트 중온포장에 대해 연구하는 사람들에게 어느 정도 도움을 주고자 일부 내용을 번역하였다. 특히, 골재와 바인더 믹싱 및 현장다짐시 온도를 낮추어 궁극적으로 $CO_2$를 저감하고자 하는 노력이 많은 아스팔트 포장관련 종사자 및 연구자들에 의해 활발히 수행되고 있다. 본 기사에서는 중온에서도 작업성을 원활하게 하기 위해 사용되는 많은 첨가제 중 Fischer-Tropsch 왁스인 Sasobit에 대해 살펴보고자 한다. 여기서 관심을 두고자 하는 점은 중온 아스팔트를 실제로 활용할 시 과연 일반 아스팔트 포장과 비교했을 때 어느 정도의 공용성(Performance)을 확보할 수 있느냐 하는 점이다. NCAT의 실내실험을 통해 알아낸 결과로는 진동다짐기를 이용하는 것이 보다 현실적이라는 것과 중온다짐에 따른 아스팔트의 동탄성 계수의 변화가 적다는 것이다. 또한 APA(Asphalt Pavement Analyzer)를 통해 소형변형의 가능성이 높지 않음을 알 수 있었으며, 중온 아스팔트를 사용함에 따른 일반적인 문제점인 수분민감성이 커지는 현상에 대해서 실험을 통해 검증한 결과, 박리방지제를 쓰는 것이 좋다는 결론을 얻었다. 전반적으로 Sasobit의 실내공용성 평가는 우수하다고 보고되고 있다.

• International Journal of Highway Engineering
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• v.10 no.4
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• pp.41-52
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• 2008

This study is to evaluate the property for the moisture susceptibility of asphalt mixtures using anti-stripping agent. Asphalt mixtures using lime, hydrated lime and liquid anti-stripping agent are evaluated through the three types of modified moisture conditioning($H_c$, V_s$, F-T). Indirect Tensile Test, that is recommended by AASHTO TP-9, which includes creep test, resilient modulus test and strength test is used to estimate moisture susceptibility. Analysis method through Energy Ratio(ER) that is proposed by Roque at University of Florida is used to evaluate moisture susceptibility and moisture resistance effects of asphalt mixtures using anti-stripping agent. As a test result, material property of asphalt mixtures was changed by moisture conditioning methods and the types of anti-stripping agent. Also, cracking resistance of accumulated moisture damage was changed by moisture conditioning methods and the types of anti-stripping agent. Based on test result, it was found that cracking resistance using Energy Ratio was differed from 10% to 30%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1D
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• pp.33-39
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• 2012

More and more pavements are suffering from damage these days due to the below-zero winter temperatures and frequent snowfalls. From this research, the freeze-thawing mechanisms of pavements will be observed, and the freeze-thawing resistance of porous asphalt concrete mixture is to be evaluated according to various assessment methods. The investigation was conducted through applying rigid and flexible pavements to freeze-thawing resistance experiments, which include various experiments such as deformation rate measurements, Lottman tests, repeated cyclic freeze-thawing experiments, stripping resistance tests and so on. Test results revealed that the porous asphalt concrete had less deformations according to temperatures compared to dense-graded asphalt concrete due to the 20% void gap. In addition, according to the freeze-thawing repetition experiments which are effected by moisture, the porous asphalt concrete mixture showed superior resistance to repeated cyclic freeze-thawing compared to other asphalt concrete mixtures due to the drainage and the voids within the specimen.