• 한국도로학회:학술대회논문집
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• 2005.11a
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• pp.161-166
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• 2005

• 한국도로학회:학술대회논문집
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• 2010.03a
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• pp.9-17
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• 2010

• 한국도로학회:학술대회논문집
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• 1999.11a
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• pp.81-88
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• 1999

• 한국도로학회:학술대회논문집
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• 2000.11a
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• pp.167-170
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• 2000

• International Journal of Highway Engineering
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• v.8 no.4 s.30
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• pp.135-143
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• 2006

This study evaluated the fatigue resistance characteristics of hot-mix recycled asphalt mixtures which were prepared by a new blending method. Since the binder of RAP shows higher viscosity without being rejuvenated in the ordinary recycled mixture, this new(modified) blending method was developed for obtaining more uniform level of binder viscosity in the recycled mixture. Cold-planned RAP was collected and mix design was performed using 15% RAP content for two virgin aggregate, gneiss and granite. Penetration grade of 60-80 asphalt was used in mixing recycled mixture together with a polymer modifier, LDPE. Indirect tensile fatigue tests were carried out to evaluate characteristics of fatigue resistance of performance of recycled asphalt mixtures. The recycled mixtures with LDPE 6% showed higher repeated loading fatigue life. Fatigue life ratio of new(N) mixing method mixtures was approximately 0.6-0.7 before aging and 0.8-1.0 after aging treatment of ordinary(O) mixing method mixture. This means the N mixture becomes stronger with aging process increase. If further aging is treated, N mixture may be showing stronger resistance than O mixture.

• International Journal of Highway Engineering
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• v.6 no.3 s.21
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• pp.9-15
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• 2004

The cracking resistance of asphalt mixtures is generally evaluated by measuring a single parameter (i.e., Tensile strength, Stiffness). However, the use of a single parameter has been questioned in the evaluation of asphalt mixture cracking performance. The focus of this study was to clearly identify the key properties and characteristics associated with the cracking resistance of asphalt mixtures. Results of fracture, creep, and strength tests at multiple loading rates performed on the modified and unmodified mixtures showed that the mixture cracking resistance was primarily affected by the rate of micro-damage accumulation. This was reflected in the m-value, without affecting the fracture energy limit. It was also observed that the short loading time (elastic) stiffness alone could not differentiate the mixture cracking resistance of the mixtures. It was concluded that the key to characterize the cracking resistance of asphalt mixture is in the evaluation of the combined effects of creep and failure limits. It was also found that a residual dissipated energy parameter measured from Superpave IDT strength test gave the quick and useful way to distinguish the difference of cracking resistance of asphalt mixtures. Failure strain in the longer-term creep test appeared to be a useful parameter for evaluating the combined effects of creep and failure limits of asphalt mixtures.

• International Journal of Highway Engineering
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• v.17 no.6
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• pp.47-54
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• 2015

PURPOSES : The objective of this study is to evaluate the early adhesive characteristic of asphalt emulsions, including polymer-modified emulsions, for chip seals using the surface energy concept, the bitumen bond strength (BBS) test, and the Vialit test. METHODS : Two general methods, the BBS test and Vialit test, were applied to investigate the bond strength and the aggregate loss, respectively. A new theory, the surface free energy (SFE) theory, was used to evaluate the adhesive characteristic between the emulsion and the aggregate. Based on the theory, the contact angles were measured, and then the surface energy components were calculated. Using those components, the work of adhesion (Wa) was calculated for each emulsion. To ensure reliable results, all the tests were performed under the same conditions, i.e., at $25^{\circ}C$ for 240 minutes of curing time. For the materials, three emulsions (CRS-2, CRS-2L, and CRS-2P) and one aggregate type (granite) were employed. RESULTS AND CONCLUSIONS : Under the same conditions, the modified emulsions showed better adhesive characteristics and curing behaviors than the unmodified emulsions. In addition, there was no significant difference between the various modified emulsions. One of the important findings is that the analysis by Wa presents more sensitive results than other methods. The results of the Wa showed that the CRS-2P emulsion has the best adhesive characteristics. Consequently, the use of modified emulsions for chip seals could prevent aggregate loss and allow open traffic earlier.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.185-190
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• 2005

Safe, economical and environment-friendly tunnel construction are required again along with social continuous development, the importance of waterproof work that is portion that actually all of user and builder can find that is embossed by tunnel construction's one of important construction. Also, ECB (Ethylen Copolymer Bitumen) sheet that is used in existing tunnel waterproofing method (ECB waterproofing method) being black because asphalt (Bitumen) is added, by purpose that make illumination of tunnel interior brightly and scar discovery eases in sheet with coating white film, but ECB that is used present according as ECB that asphalt is added does not satisfy high tensile strength of construction field, quality standard of extension. Also ECB denigrates color of black M/B that asphalt is excepted.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.8
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• pp.4028-4032
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• 2013

Recycling method for pyrolyzed carbon black from pyrolysis process of waste tires is needed. Carbon black from pyrolysis of waste tires was used to modify and improve the permanent deformation properties of asphalt binder. 0%, 5%, 10%, 15% and 20% of pyrolyzed carbon black was mixed. Couple of laboratory tests, such as softening point, flash point test, rotational viscometer test and dynamic shear rheometer test, were carried out. The use of pyrolyzed carbon black incresed the softening point, rotational viscosity at 135oC, and resistance of permanent deformation.

• International Journal of Highway Engineering
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• v.9 no.1 s.31
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• pp.57-67
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• 2007

Many researches have recently discussed about the film thickness as a good substitute or supplement for VMA or other volumetric criteria in the design procedure. Some researchers have not only proposed the specific number for the recommended film thickness, but also introduced the new calculation procedures or concepts. Each model (index model and the virtual model) has its own advantages and disadvantages in terms of the ability to account for the volumetric properties of the mixture. In this paper, the modified virtual model was proposed to combine advantages from both models. However, it cannot be disregarded the way to determine the appropriate particle shape factors for different sources and sizes of aggregates. In order to evaluate the different calculation methods, mixtures with two aggregate sources and eight gradations were designed based on the dominant aggregate size range (DASR) porosity concept. Superpave indirect tensile test (IDT) and asphalt pavement analyzer (AEA) test were used to describe the performance of mixtures. Test results indicated that the virtual model, which is the same to the modified virtual model for sphere 1:1 case, is better than the conventional standard model to define the range of the film thickness to have better performance of asphalt mixtures.