• 한국농공학회지
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• 제42권
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• pp.85-91
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• 2000

Dwindling supplies and increasing costs of conventional highway materials used in road construction as well as concerns over shrinking landfill spaces prompt researchers to investigate the use of waste products, such as fly ash, as substitute materials in highway construction. The highway industry is capable of utilizing waste materials in large quantities if their effect on pavement performance proves to be technically, economically and environmentally satisfactory. This research examines the effects of fly ash when used as partial replacement of aggregate in asphaltic concrete mixtures. And measuring the effect of fly ash on bulk specific gravity, air void, indirect tensile strength (ITS) under dry and wet conditioning as well as the tensile strength ratio (TSR) of asphaltic concrete mixture. The results indicated that asphaltic concrete mixtures containing 2% and 5% fly ash produced about the same TSR value as control mixture. And all of the mixtures met the minimum ITS and TSR requirements established by the South Carolina Department of Transportation (SC DOT) for Type 1A surface courses. At this point and with this limited study, these asphaltic concrete mixtures is recommended in several applications such as parking lot, secondary roads and driveways.

• 한국도로학회논문집
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• 제19권2호
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• pp.127-135
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• 2017

PURPOSES: The objective of this study is to evaluate the effect of anti-stripping on asphalt mixtures constituting anti-stripping agents. METHODS : Based on the literature review, asphalt mixture added with anti-stripping agents was prepared, and these asphalt mixtures were evaluated for anti-stripping properties for each anti-stripping agent through various lab tests, namely, tensile strength ratio (TSR), dynamic immersion test, uniaxial compression test, and indirect tensile strength test (IDT). The liquid anti-stripping agents used in the lab test were premixed with each asphalt binder (PG 64-22, PG 76-22) before being mixed with the aggregate. RESULTS :The result of the TSR test revealed that the effect of anti-stripping was highest when hydrated lime and liquid anti-stripping agent W were added. The correlation coefficient $R^2$ between the TSR result and cohesion ratio is 0.99, which indicates that the sensitivity of the TSR to moisture damage is reliable from the mechanical point of view. The covering ratio of the asphalt binder to the liquid anti-stripping agent W was determined to be higher than that to the other liquid anti-stripping agents. CONCLUSIONS :It is considered that the improved moisture resistance of asphalt mixture as a result of the use of anti-stripping agents can reduce the incidence of various pavement damages such as portholes caused by stripping, and the performance life of the asphalt road pavement can be prolonged.

• 한국도로학회논문집
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• 제16권4호
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• pp.45-50
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• 2014

PURPOSES : The objective of this study is to analyze the performance of anti-stripping agent depending on its type and content to reduce pothole, an increasing pavement distress due to abnormal climate intensity. METHODS : In the past years, U.S and many countries in Europe use hydrated lime and liquid anti-stripping agent in asphalt mixtures. Hydrated lime or liquid anti-stripping agent is substituted for filler and binder, respectively, to improve the anti-stripping property of asphalt mixtures. To investigate this, indirect tensile strength test was performed and TSR values were compared for different content of hydrated lime and types of liquid anti-stripping agent in asphalt mixture. RESULTS : Test results indicate that hydrated lime remarkably increased the asphalt mixture performance on anti-stripping denoted by the increased in TSR values from 55% to 100%. Liquid anti-stripping agent also increased the value of TSR but not significant. In addition, depending on the types of aggregate, TSR values and effect of liquid anti-stripping were different. CONCLUSIONS : Using anti-stripping agents improve the anti-stripping property of asphalt mixture especially hydrated lime; however, more experiments should be conducted to improve the reliability about the effect of liquid anti-stripping agent.

• 한국도로학회논문집
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• 제19권2호
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• pp.137-142
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• 2017

PURPOSES :The objective of this study is to evaluate the performance of asphalt mixtures containing inorganic additive and a high content of reclaimed asphalt pavement (RAP). METHODS : The laboratory tests verified the superior laboratory performance of inorganic additive compared to cement, in cold recycled asphalt mixtures. To investigate the moisture susceptibility of the specimens, tensile strength ratio (TSR) tests were performed. In addition, dynamic modulus test was conducted to evaluate the performance of cold recycled asphalt mixture. RESULTS :It was determined that NaOH solution mixed with $Na_2SiO_3$ in the ratio 75:10 provides optimum performance. Compared to Type B and C counterparts, Type A mixtures consisting of an inorganic additive performed better in the Indirect tensile strength test, tensile strength ratio test, and dynamic modulus test. CONCLUSIONS : The use of inorganic additive enhances the indirect strength and dynamic modulus performance of the asphalt mixture. However, additional experiments are to be conducted to improve the reliability of the result with respect to the effect of inorganic additive.

• 한국도로학회논문집
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• 제19권5호
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• pp.13-20
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• 2017

PURPOSES : This research was a laboratory study for evaluating the Reclaimed Asphalt Pavement (RAP) mixture added developed rejuvenator for warm mix recycling. Waste asphalt mixtures occupy about 18.2% of construction wastes in Korea. Moreover, most rejuvenators were imported from Europe or the U.S. Therefore, improving usage of RAP with a developed rejuvenator material provides environmental protection at a reduced cost. METHODS : The specimen used for this experiment was performed by only using RAP. A suitable rejuvenator for Target PG was then added. In addition, a conventional rejuvenator was selected to compare performance and specimens introduced with the same procedure as the developed rejuvenator was prepared. In order to evaluate rutting resistance and water susceptibility, we conducted a deformation strength test, a tensile strength ratio test, and a dynamic immersion test with the prepared mixtures. RESULTS :Laboratory test results indicated that both the developed additive and conventional additive improved performance of the recycled asphalt mixtures compared to mixtures without the rejuvenator. In addition, the deformation strength test and TSR test results satisfied standards for domestic recycling asphalt mixtures. The dynamic immersion test showed that the developed rejuvenator has superior scaling resistance than the conventional rejuvenator. CONCLUSIONS : In terms of rutting resistance and moisture susceptibility, the warm mix recycled asphalt mixtures with the developed rejuvenator appeared to effectively recovered performance.

• 대한토목학회논문집
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• 제39권4호
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• pp.523-530
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• 2019

포트홀 발생 및 관련 교통사고 건수는 매년 꾸준히 증가하는 추세이며 이에 따른 인명피해, 차량파손에 따른 비용손실 등 도로 이용자의 직 간접적인 피해를 증가시키고 있다. 일반적으로 아스팔트 혼합물은 생산과정부터 시공 후 공용에 따라 지속적으로 노화가 진행된다. 포장 노화는 균열과 수분침투로 박리를 야기하고 반복적인 윤하중에 의해 포장구조를 약화시켜 포트홀을 유발하게 된다. 본 연구에서는 노화가 아스팔트 콘크리트 포장에 미치는 영향을 검토하기 위해 노화정도에 따른 부착성능 평가와 수분민감성 평가를 수행하였다. 연구결과 노화에 따라 아스팔트 바인더의 점성이 증가해 부착강도가 2~3배 이상 증가하였다. 또한 가속 노화시킨 아스팔트 혼합물의 경우 간접인장강도의 증가뿐만 아니라 TSR 값도 4.2~8.9 % 증가하는 것으로 나타났다. 이에 따라 골재에 아스팔트 바인더가 피복된 상태에서 노화가 진행될 경우 아스팔트 바인더와 골재의 부착력이 증가하여 박리 저항성이 향상되는 것으로 분석되었다.

• 한국도로학회논문집
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• 제20권1호
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• pp.47-58
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• 2018

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 $G*/sin{\delta}$and the dynamic shear modulus (${\mid}G*{\mid}$). 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 $G*/sin{\delta}$ 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.

• 한국도로학회논문집
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• 제3권4호
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• pp.105-116
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• 2001

본 연구는 주물고사를 이용한 아스팔트 콘크리트와 주물고사의 물리적 화학적 특성을 비교 분석하는 것이다. 주물고사의 아스팔트 콘크리트 적용성을 평가하기 위하여 XRF, SEM, 제타전위를 측정하여 주물고사의 물리 화학적 특성을 알아보았다. 주물고사 아스팔트 콘크리트의 박리저항성을 향상시키기 위하여 박리방지제(소석회(Hydrated lime), 액상박리방지제)를 사용하였다. 그리고 주물고사 아스팔트 콘크리트 혼합물의 인장특성과 내구성 향상을 위하여 LDPE를 사용하였다. 또한 주물고사 아스팔트 콘크리트의 공용성을 알아보기 위하여 간접인장강도, 수분취약성시험, 동결 융해시험, 반복주행시험을 수행하였다. 시험결과 주물고사 아스팔트 콘크리트의 역학적 특성이 일반 아스팔트 콘크리트에 비해 같거나 향상되는 것으로 나타났다. 따라서 주물고사를 아스팔트 콘크리트에 재활용할 수 있다는 결론을 얻었다.

• 한국도로학회논문집
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• 제6권4호
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• pp.91-100
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• 2004

본 연구는 차도용 칼라 역청 콘크리트의 적용성을 평가하기 위하여 수행되었다. 칼라 역청 포장은 차도가 아닌 보행자 도로나 자전거 도로에 사용되어 왔다 본 연구에서 바인더 개질 및 혼합물 강성의 증진을 위하여 두 가지폴리머가 사용되었다. 또한 갭입도 혼합물에서 나타나는 침강현상을 방지하기 위하여 폐신문지를 사용하였다 마샬안정도, 간접인장강도, 동결-융해 및 인공노화 처리 전 후의 인장강도비, 소성변형 저항성, 피로수명을 측정하였다. LDPE 개질된 칼라 역청 콘크리트는 일반 아스팔트 혼합물에 비해 높은 안정도와 인장강도를 나타냈으며, 특히 소성변형 저항성에서 많은 향상을 가져왔다. Rosin 개질된 칼라 역청 콘크리트는 일반 아스팔트 혼합물보다 높은 안정도와 동결융해저항성을 보였으며, 특히 간접인장강도에서 많은 향상을 보였다. LDPE +Rosin의 개질은 거의 대부분의 역학적 특성의 증가를 가져왔다. 따라서 본 연구에서 사용된 칼라 역청 콘크리트 혼합물은 기존 AP-3를 사용한 아스팔트 콘크리트 혼합물과 비교해 역학적 특성이 비슷하였으며, 모든 혼합물은 차도용 시방 규정을 만족하였다. 그리고, 이를 LDPE와 Rosin으로 개질할 경우 포장의 공용성능이 더욱 향상될 것으로 보여 차도용으로 충분히 사용 가능함을 확인하였다.

• 한국도로학회논문집
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• 제16권1호
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• pp.31-39
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• 2014

PURPOSES : Surface treatment material for pavement preventive maintenance should be inspected field applicability. This study(Part II) aimed to checkup coating characteristics and performance analysis using lab and field tests. The hydrophobic - low viscosity filling material for pavement preventive maintenance is presented in Part I, which is a series of companion study. METHODS : Relative comparison between general asphalt mixtures and surface treatment asphalt mixtures are analyzed and measured for the field application such as indirect tensile strength ratio(TSR), abrasion resistance, crack propagation resistance, temperature resistance, coating thickness, permeability resistance and skid resistance in terms of british pendulum number(BPN). RESULTS : It is found that TSR, crack propagation resistance and permeability resistance is increased as against uncoated asphalt specimen. Abrasion resistance and temperature resistance is secured from the initial coating thickness point of view, which is about 0.2~0.3mm. Skid resistance on the surface treatment pavement is satisfied with the BPN criteria of national highway because of exposed aggregate and crack sill induced pavement deterioration and damage cracks. CONCLUSIONS : The hydrophobic - low viscosity surface treatment material for pavement preventive maintenance is validated on field applicability evaluation based on quantitative analysis of coating thickness and performance analysis using lab and field tests.