Browsing by Author "Moon, Ki Hoon"

Now showing 1 - 6 of 6
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    Air Voids Testing for MnROAD Cells
    (Minnesota Department of Transportation Research Services Section, 2010-07) Turos, Mugurel; Moon, Ki Hoon; Marasteanu, Mihai
    This report summarizes the experimental work performed on cores extracted from various cells at MnROAD to determine the air void content of the different asphalt mixtures used in these cells. Analysis of the data was not part of this study.
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    Asphalt Mixture and Binder Fracture Testing for 2008 MnROAD Construction
    (Minnesota Department of Transportation, 2009-12) Marasteanu, Mihai; Moon, Ki Hoon; Turos, Mugurel
    This report summarizes the results of an experimental effort to characterize the low-temperature behavior of asphalt mixtures and binders from the recently reconstructed cells at the MnROAD facility. In depth analysis of the data was not part of this study; this will be accomplished in several concurrent research projects.
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    Comparison of thermal stress calculated from asphalt binder mixture creep compliance data
    (2010-08) Moon, Ki Hoon
    Low temperature cracking represents a significant problem in asphalt pavements built in Northern US and Canada. As temperature decreases rapidly, thermal stresses develop in the restrained surface layer and, when the temperature reaches a critical temperature, cracking occurs. In this thesis, statical analyses were used to compare thermal stresses that develop in an idealized asphalt pavement layer calculated from experimental data obtained with three different test methods: 1) Asphalt mixture creep test using Bending Beam Rheometer (BBR) 2) Asphalt mixture testing using Indirect Tensile Test (IDT) 3) Asphalt binder creep test using BBR and an empirical Pavement Constant Thermal stresses calculated using mixture BBR and mixture IDT data were reasonably identical. Thermal stresses calculated using binder BBR data and an empirical Pavement Constant were significantly different than the other calculated thermal stresses. The effect of physical hardening on thermal stress evaluation was investigated for a limited number of materials and it was found that this effect significantly affect thermal stress magnitude.
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    Investigation of asphalt binder and asphalt mixture low temperature properties using analogical models
    (2012-09) Moon, Ki Hoon
    In very cold climates, thermal cracking is the main distress that affects asphalt pavements. At these temperatures, asphalt materials become very stiff and reach stress values higher than their strength, and cracks form and propagate. Asphalt pavements are built with asphalt mixtures, which are composite materials that contain coarse and fine aggregates of specific sizes bound together with asphalt binder, a highly temperature susceptible viscoelastic material. In past years, micromechanical composite material models were used to explain the relationship between asphalt binder and asphalt mixture stiffness properties. Asphalt mixtures were assumed as two-phase materials or as three-phase material. Due to low order microstructural information (volume fractions) used in these models, the asphalt mixture stiffness was significantly under predicted. Recently, a semi-empirical model called Hirsch model and a transformation based on mechanically analog models, called ENTPE (École Nationale des Travaux Publics de l'État) transformation, were successfully used to predict asphalt mixture creep stiffness from asphalt binders creep stiffness and vice-versa, at low temperatures. In this thesis, these two models are further investigated to understand the physical meaning of the models parameters and to establish a link between the microstructure of mixtures and these parameters. This will be accomplished by analyzing digital images of the mixtures to obtain extensive information on their aggregate structure and by performing extensive three point bending creep tests on asphalt mixtures and their component asphalt binders. It is expected these results will significantly improve the design of asphalt mixture with good thermal cracking resistance.
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    Investigation of Low Temperature Cracking in Asphalt Pavements National Pooled Fund Study – Phase II
    (Minnesota Department of Transportation, 2012-08) Marasteanu, Mihai; Buttlar, William; Bahia, Hussain; Williams, Christopher; Moon, Ki Hoon; Teshale, Eyoab Zegey; Falchetto, Augusto Cannone; Turos, Mugurel; Dave, Eshan; Paulino, Glaucio; Ahmed, Sarfraz; Leon, Sofie; Braham, Andrew; Behnia, Behzad; Tabatabaee, Hassan; Velasquez, Raul; Arshadi, Amir; Puchalski, Sebastian; Mangiafico, Salvatore; Buss, Ashley; Bausano, Jason; Kvasnak, Andrea
    The work detailed in this report represents a continuation of the research performed in phase one of this national pooled fund study. A number of significant contributions were made in phase two of this comprehensive research effort. Two fracture testing methods are proposed and specifications are developed for selecting mixtures based on fracture energy criteria. A draft SCB specification, that received approval by the ETG and has been taken to AASHTO committee of materials, is included in the report. In addition, alternative methods are proposed to obtain mixture creep compliance needed to calculate thermal stresses. Dilatometric measurements performed on asphalt mixtures are used to more accurately predict thermal stresses, and physical hardening effects are evaluated and an improved model is proposed to take these effects into account. In addition, two methods for obtaining asphalt binder fracture properties are summarized and discussed. A new thermal cracking model, called "ILLI-TC," is developed and validated. This model represents a significant step forward in accurately quantifying the cracking mechanism in pavements, compared to the existing TCMODEL. A comprehensive evaluation of the cyclic behavior of asphalt mixtures is presented, that may hold the key to developing cracking resistant mixtures under multiple cycles of temperature.
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    Performance of Taconite Aggregates in Thin Lift HMA: Final Report - January 31, 2012
    (University of Minnesota Duluth, 2012) Zanko, Lawrence M; Johnson, Ed; Marasteanu, Mihai; Patelke, Marsha Meinders; Linell, David; Moon, Ki Hoon; Oreskovich, Julie A; Betts, Ray; Nadeau, Lynette; Johanneck, Luke; Turos, Mugur; DeRocher, Will
    This project was undertaken to advance the knowledge of the beneficial uses of taconite mining coarse tailings (taconite fine aggregate) for thin lift hot mix asphalt (HMA), to facilitate technical information gathering and marketing of such uses and properties, and to encourage the beneficial use of recycled/byproduct materials like durable and wear- and skid-resistant taconite (Mesabi) aggregates, recycled asphalt pavement (RAP), and asphalt shingles. In combination, the use of each is highly desirable because it promotes resource conservation, safety, and energy-saving. Outcomes of this study suggest that Mesabi rock and tailings products show promise as components of 4.75-mm Dense-graded, Stone Matrix Asphalt, and Ultra-Thin Bonded Wearing asphalt mixtures. Laboratory and field investigations of taconite tailings should continue. The Mesabi rock can be incorporated in standard Superpave, SMA, and fine/sand asphalt mixtures in upcoming construction projects. In each case construction and long term field performance should be evaluated. The investigators conclude that taconite-based thin lift HMA mixes that also incorporate RAP should be recognized as an environmentally sound, i.e., combining the use of byproduct and recycled/reclaimed materials, and high-quality option for HMA pavement rehabilitation and preservation. Collectively, the material testing results suggest that thinner wear-course pavements made from appropriately designed taconite-based mixes can match or exceed the service life of conventional MnDOT Level 4 mixtures. If extended service life is realized, then taconite fine aggregate could be a cost-effective choice at end-user locations where high-quality local aggregate sources are lacking or absent. These enhanced performance attributes can add intrinsic value to taconite materials and make them more desirable to use and more cost-effective to transport longer distances, thereby improving and broadening their near- and long-term potential for regional and national highway infrastructure projects.