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최적화된 시멘트 아스팔트 모르타르(CAM) 설계를 위한 다양한 유화제가 적용된 아스팔트 바인더의 유변학적 평가
조상갑,문기훈,Augusto Cannone Falchetto,강일환,박태순 한국아스팔트학회 2023 한국아스팔트학회지 Vol.13 No.1
Designing an optimized Cement Asphalt Mortar (CAM) is essential not only for providing smoother riding quality on road pavements but also for reducing vibration and noise on railways. In producing CAM material, one of the most crucial factors is the selection of asphalt binders with good mixing compatibility when combined with various emulsifying agents. Many emulsifying agents and corresponding modified asphalt binders have been studied and developed over the past decades to improve the material performance of the asphalt mixture. However, the mechanical properties of blends of asphalt binder and emulsifying agents were not studied and considered significantly from a perspective of an application in railways. This demands a dedicated evaluation of these asphalt binder blends using various mathematical models in the attempt to design better-performing CAM. In this paper, a rheological evaluation of asphalt binder mixed with three emulsifying agents was performed with different mathematical models, including a newly developed formulation named C2MKP model. Dynamic Shear Rheometer (DSR) tests were conducted as experimental work. Complex modulus and phase angle results were computed; then, the corresponding master curve was generated based on different mathematical models. All the results were compared visually on a wide range of given test frequencies. It was found that modified asphalt binder can provide similar rheological performance compared to the conventional asphalt binder, suggesting that modified asphalt binder can be successfully adopted in the CAM production for railways.
조상갑,문기훈,Augusto Cannone Falchetto,강일환,박태순 한국철도학회 2023 한국철도학회논문집 Vol.26 No.2
Designing an optimized Cement Asphalt Mortar (CAM) is essential not only for providing smoother riding quality on road pavements but also for reducing vibration and noise on railways. In producing CAM material, a crucial factor is the selection of asphalt binders with good mixing compatibility when combined with various emulsifying agents. Many emulsifying agents and corresponding modified asphalt binders have been studied and developed over the past decades to improve the material performance of the asphalt mixture. However, mechanical properties of blends of asphalt binder and emulsifying agents have not been studied or considered significantly from a perspective of application to railways. This demands a dedicated evaluation of these asphalt binder blends using various mathematical models in an attempt to design a better-performing CAM. In this paper, a rheological evaluation of asphalt binder mixed with three emulsifying agents was performed with different mathematical models, including a newly developed formulation called the C2MKP model. Dynamic Shear Rheometer (DSR) tests were conducted as experimental work. Complex modulus and phase angle results were computed; then, a corresponding master curve was generated based on different mathematical models. All the results were compared visually on a wide range of given test frequencies. It was found that modified asphalt binder can provide rheological performance similar to that of conventional asphalt binder, suggesting that modified asphalt binder can be successfully adopted in CAM production for railways.
시그모이드함수 기반으로 아스팔트 바인더의 극한영역 모델링 연구
조상갑,박태순,문기훈 한국아스팔트학회 2023 한국아스팔트학회지 Vol.13 No.2
This study was performed to predict the viscoelastic behavior on Asphalt binder by means of mathematic modeling approach. As testing material, PG 64-22 asphalt binder was prepared. The Dynamic Shear Rheometer (DSR) test was performed as mechanical experimental activities of asphalt binder. As result, complex shear modulus of given asphalt binder at various temperature and frequency conditions was computed then generated. To predict and analyze the global mechanical performance of tested asphalt binder from DSR test results, a master curve construction and generation approach was considered. In the previous studies, two mathematical models: Sigmoidal and Richards models, were considered to predict the global complex shear modulus pattern of given asphalt binders. However, not many studies considered on developing more advanced mathematical models on global complex shear modulus behavior than the previous ones in the past decades. In this paper, three different mathematical modeling approaches for complex shear modulus master curve construction were introduced. It was found that the newly developed three mathematical models can successfully explain and predict global complex shear modulus of asphalt binder compared to the previous ones. This means there can be more options for DSR test results prediction. More experimental works and corresponding analyses are needed to further strengthen the findings in this paper as a future research.
조상연,이수갑 한국소음진동공학회 1997 소음 진동 Vol.7 No.6
Combustion instability is a common phenomenon in a ducted flame burner and is known as accompanying low frequency oscillation. This is due to the interaction between unsteady heat release rate and sound pressure field, that is, thermoacoustic feedback. In Rayleigh criterion, combustion instability is triggered when the heat addition is in phase with acoustic oscillation. A Rijke type burner with a pre-mixed flame is built for investigating the effect of Reynolds number and equivalence ratio on thermoacoustic oscillation. The results suggest that the frequency of max, oscillation is dependent on Reynolds number and equivalence ratio whereas its magnitude is not a strong function of these two parameters.
저속 유동장이 있는 원통형 연소기에서의 열-음향학적 불안정에 대한 능동 제어 연구
조상연,이용석,이수갑,배충식 한국소음진동공학회 1998 소음 진동 Vol.8 No.5
Combusion instability due to thermoacoustic feedback in a ducted combustor usually excites severe noise and vibration, which could lead to result in the failure of the system or environmental dispute. In the present study, an active noise control(ANC) method with an adaptive algotithm is hired to suppress instability which has very discrete behavior in the frequency domain. Especially a feedback system is composed to evade hot environment of the combustor, and as a preliminary, the performance and stability of the controller is chekced by simulating the real situation with harmonic waves. Application to the real combustor showed serious reductions in sound pressure level by 20∼30 dB. It was also shown that the selected control system was very stable and effective.
Mechanical performance evaluation of taconite aggregate in asphalt pavement construction
Augusto Cannone Falchetto,문기훈,조상갑 한국아스팔트학회 2022 한국아스팔트학회지 Vol.12 No.1
Using alternative aggregate source is essential in asphalt pavement industry not only for saving construction budget but also for mitigating environmental pollution issue. In U.S. northern Minnesota territory, amount of taconite aggregate: a byproduct of taconite mining industries, are produced annually. If taconite aggregate is successfully used as an alternative aggregate source, more economical and environment friendly asphalt mixture can be achieved. Many studies presented the possibility of taconite aggregate application in road construction. In this paper, suitability investigation of using taconite aggregate is performed by means of mechanical test: low temperature Indirect Tensile (IDT) creep test. A parameter for low temperature cracking resistance: creep stiffness (and corresponding relaxation modulus) result, is computed then compared visually. It was found that the asphalt mixture mixed with coarse taconite aggregate and limestone filler presented reasonable mechanical performance compared to the conventional asphalt mixture. This finding provides possibility of taconite aggregate application in actual asphalt pavement construction.
Augusto Cannone Falchetto,문기훈,조상갑 한국아스팔트학회 2022 한국아스팔트학회지 Vol.12 No.1
It is well known that application of alternative aggregate material in asphalt pavement area is crucial not for saving construction budget but for mitigating environmental pollution. Several research efforts: for finding alternative aggregate material, were performed in U.S. during the past decades. One of the research achievements is application of taconite aggregate: a byproduct of taconite mining industries in northern Minnesota, U.S., in asphalt pavement construction. Some studies performed performance evaluation of taconite aggregate added mixture with various mechanical testing procedure. However, not many studies considered pavement design performance simulation, evaluation and comparison in case of taconite aggregate application. In this paper, performance evaluation of taconite aggregate mixture by means of composite pavement design simulation using AASHTOWare-Pavement (MEPDG: Mechanical-Empirical Pavement Design Guide) was considered. Reasonable and comparable pavement performance was found when taconite aggregate is applied compared to the conventional asphalt mixture.