• Advances in concrete construction
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• 제10권6호
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• pp.515-526
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• 2020

Cold-mixed asphalt mixture is a widely recommended asphalt pavement materials with potentially economic and environmental benefits. Due to the reduction of natural non-renewable mineral resources, powder minerals with similar properties are considered as new mineral fillers in asphalt mixtures. This study explored the feasibility of using cement to replace natural limestone powder (LP) in emulsified asphalt concrete modified by styrene-butadiene styrene copolymer. The experimental tests, including compressive strength, Marshall stability as well as moisture susceptibility test, were used to investigate the mechanical properties, the Marshall stability, flow value, as well as the moisture damage. In addition, the influence of material composition on the performance of asphalt concrete is explained by the microstructure evolution of the pore structure, the interface transition zone (ITZ), and the micromorphology. Due to mineralogical reactivity of cement, its replacement part of LP improved the mechanical properties, Marshall stability, but it will reduce the moisture susceptibility and flow value. This is because with the increase of the cement substitution rate, the pore structure of the asphalt concrete is refined, the width of ITZ becomes smaller, and the microstructure is more compact. In addition, asphalt concrete with a larger nominal particle size (AC-16) has relatively better performance.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1991년도 가을 학술발표회 논문집
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• pp.1-4
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• 1991

Relationship between againg and characteristic change of asphalt is not well known through asphalt rheolopy. Therefore, this study was conducted to evaluate characteristic change of asphalt cement due to againg based on experimental results of chromatogram and selected physical properties. Currently, three virgin asphalt cements were tested for physical properties and chromatograms before and after artificially conditioning for againg. Results in the current study showed that againg caused significant changes of physical properties and increase of larger size molecules and approximately corresponding reduction of smaller size molecule in asphalt cement molecular size distribution.

• 복합신소재구조학회 논문집
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• 제6권3호
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• pp.69-76
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• 2015

The purpose of this paper is to find an limitation to detect the defect of damaged asphalt pavement structures for infrared thermography. We use heat source of a natural light to detect the defect efficiently. The heat source was applied to the asphalt specimens. Four asphalt specimens were used: one was the asphalt containing depth of 1cm internal timber, two was the asphalt containing depth of 2cm internal void, Three was the asphalt containing depth of 3cm internal timber and four was not the asphalt containing internal timber. It was found that the depth of 3cm internal timber could be detected by this method. In addition, we used the image processing to make the damage zone displayed clear in the image obtained from the thermographic operation.

• 한국재난정보학회 논문집
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• 제3권1호
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• pp.21-35
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• 2007

The principal objective of this research is to evaluate the laboratory mechanical characteristics of color asphalt binders and mixtures. The dynamic shear rheometer (DSR) tests were performed to analyze the viscous and elastic behavior of asphalt binders. Various tests were also conducted to investigate the laboratory performance characteristics of color asphalt mixtures. The test results revealed that the values of $G^*$ and ${\delta}$ of modified color binders were higher than those of the conventional binders at low temperatures. These results are expected to increase the thermal cracking resistance of asphalt mixtures at low temperatures. It should be noted that the color asphalt mixtures with modified asphalt binder can be widely used as a common pavement material with a proper mix design.

• 한국도로학회논문집
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• 제20권1호
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• pp.59-67
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• 2018

PURPOSES : This paper presents a mix design method for using steel slag as an aggregate for asphalt mixtures. METHODS : Steel slag has a different density and absorption rate than natural aggregates. The asphalt content was calculated according to the steel slag characteristics, and the formula for aggregate-gradation correction was presented. RESULTS : The asphalt mix was designed using the proposed equations. Using the proposed mix design method, it was possible to design the asphalt mixture according to the target-usage amount of the recycled aggregate. CONCLUSIONS : The suggested method can be used for asphalt mix design using aggregates with different densities and absorption rates. It is expected to contribute to quality improvement by ensuring accurate calculation of mixing ratios for steel slag asphalt mixtures.

• 한국환경보건학회지
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• 제1권1호
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• pp.32-35
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• 1974

Acidic substances contained in asphalt are affect upon emulsitiability of asphalt and its adhesion with aggregates, and therfore, detemination of acidity of asphalt is of important one. However, there has not been established a method of precisely determining the acidity of asphalt. This paper reports on an improved color-indicator titration method, by which the acid number of asphalt is determined. By treating benzene solution of asphalt with alcohol, acidic constituents were selectively extracted into alcohol solution, while asphaltic matters precipitated. A color-indicator titration method then was applied to the resultant faint-colored solution. The change of color at end point was clearly observed, and the results were obtained with good reproductivity and checked well with the results by the I.P. 177/64 method. Alcohols having not more than three cabon atoms have been found suitable for extraction.

• 한국재난정보학회 논문집
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• 제6권1호
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• pp.28-43
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• 2010

This paper presents the field applications of polymer-modified warm asphalt mixture which can reduce the temperature during the production and field constructions. The amount of fuel consumptions and $CO_2$ diffusions can be reduced by much using the polymer-modified warm asphalt mixture instead of the conventional polymer-modified asphalt mixture. According to the research results, the polymer-modified warm asphalt mixture can be utilized without additional temperature increasement and performance sacrifice during the plant production and public service, respectively. As a result, it is considered that the application of the polymer-modified warm asphalt mixture has the potential of convenience in constructions management and reducing the environmental damages.

• Elastomers and Composites
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• 제57권4호
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• pp.215-221
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• 2022

In this study, high-penetration asphalt with low greenhouse gas emissions was used in the asphalt mixing process to reduce the carbon emissions during the reaction due to its capacity to be produced even at low temperatures. In effect, cationic, anionic, and non-ionic dispersants were added and mixed in different feeding ratios, seeking an effective dispersion of the modifiers (SIS, PS, TPEE, and SEBS) into the high-penetration asphalt matrix and forming an asphalt binder with a melting point of 120 ℃. The compatibility of the modifiers and the high-penetration asphalt was examined using SEM and DSC techniques, and the role of NDP-1 as a dispersant was carefully investigated with respect to dissolution time. The analyses showed that: (1) the dispersibility of the asphalt binder is good when the non-ionic dispersant is used; (2) as the concentration of the non-ionic dispersant increases, the dissolution time decreases and the domain size contracts; (3) the ND70-PS has the shortest dissolution time, the lowest agglomeration rate, and a single Tg value.

• 한국도로학회논문집
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• 제18권4호
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• pp.19-28
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• 2016

PURPOSES : Long-life asphalt pavements are used widely in developed countries. In order to be able to devise an effective maintenance strategy for such pavements, in this study, we evaluated the performance of the long-life asphalt pavements constructed along the national highways in South Korea. Further, an economic evaluation of the long-life asphalt pavements was performed based on a life-cycle cost analysis. We aimed to devise a model for evaluating the performance of long-life asphalt pavements using the national highway pavement management system (PMS) database as well as for analyzing the economic feasibility of such pavements, in order to promote their use in South Korea. METHODS : The maintenance history and pavement performance data were obtained from the national highway PMS database. The pavement performances for a total of 292 sections of 10 lanes (5 northbound lanes and 5 eastbound lanes) of national highways were used in this study. Models to predict the performances of hot mix asphalt (HMA) and long-life asphalt pavements under two distinct traffic conditions were developed using a simple regression method. Further, the economic feasibility of long-life asphalt pavements was evaluated using the Korea Pavement Management System (KoPMS). RESULTS : We developed service-life prediction models based on the traffic volume and the equivalent of single-axle load and found that long-life asphalt pavements have service lives 50% longer than those of HMA pavements. Further, the results of the economic analysis showed that long-life asphalt pavements are superior in terms of various economic indexes, including user cost, delay cost, total cost, and user benefits, even though their maintenance cost is higher than that of HMA pavements. A comparison of the economic feasibilities of the various groups showed that group A is superior to HMA pavements in all aspects except in terms of the maintenance criterion (crack 20% or higher) as per the NPV index. However, the long-life asphalt pavements in group B were superior in terms of the maintenance criterion (crack 25% or higher) regardless of the economic feasibility. CONCLUSIONS : The service life of long-life asphalt pavements was found to be approximately 50% longer than that of HMA pavements, regardless of the traffic volume characteristics. The economic feasibility of long-life asphalt pavements was evaluated based on the KoPMS. The results of the economic analysis were the following: long-life asphalt pavements are exceptional in terms of almost all factors, such as user cost, delay cost, total cost, and user benefit; however, the exception is the maintenance cost. Further, the economic feasibility of the long-life asphalt pavements in group B was found to be better than that of the HMA pavements (crack 25% or higher).

• 대한토목학회논문집
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• 제28권2D호
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• pp.243-248
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• 2008

아스팔트 포장에서 발생하는 수분손상은 우수 등에 의한 수분 침투로 아스팔트 혼합물 내의 접착력과 점착력이 손상되면서 발생하는 현상으로서, 아스팔트 포장의 주요 파손에 영향을 미치는 원인의 하나로 알려져 있다. 본 연구에서는 아스팔트 포장에서 발생하는 수분손상을 아스팔트 혼합물의 실내 물성 특성으로 규명하고자, 기존의 간접인장시험과 수정 라트만 시험 방법을 이용하여 국내의 일반 및 SBS 개질 아스팔트 혼합물에 대해 반복 수침 및 다양한 온도 영역에서 아스팔트 혼합물의 물성 변화와 수분 저항성 특성을 평가하였다. 이를 통해 아스팔트 혼합물의 물성(회복탄성계수, 간접인장강도, 파괴에너지, 크리프 변형에너지) 변화가 반복적인 수침에 따른 수분손상과는 높은 상관성을 나타내었으며, 수침 횟수별로 다른 감소 경향을 나타내는 결과를 도출하였다. 그리고 재료 종류별로는 반복 수침에 따른 시험 물성값의 손실률은 모든 온도 영역에서 SBS 개질 아스팔트 혼합물이 일반 아스팔트 혼합물에 비해 낮은 경향을 나타내는 것으로 분석되었다. 결론적으로, 현행 아스팔트 혼합물의 수분손상 특성을 평가하는 방법은 단기적인 수침 조건과 단일 시험 물성에 의해 평가됨으로서 변별력 있는 기준으로 사용하는데 한계가 있는 것으로 판단된다. 이에 아스팔트 혼합물의 장기적인 수분손상 특성 및 변별력 있는 재료 물성의 평가를 위해서는 반복적인 수침 조건과 함께 다양한 물성 기준의 적용이 고려되어야 할 것으로 판단된다.