Browsing by Subject "Asphalt binder"

Now showing 1 - 5 of 5
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    Determination of Optimum Time for the Application of Surface Treatments to Asphalt Concrete Pavements - Phase II
    (Minnesota Department of Transportation, 2008-06) Marasteanu, Mihai; Velasquez, Raul; Herb, William; Tweet, John; Turos, Mugur; Watson, Mark; Stefan, Heinz G.
    Significant resources can be saved if reactive type of maintenance activities are replaced by proactive activities that could significantly extend the pavements service lives. Due to the complexity and the multitude of factors affecting the pavement deterioration process, the current guidelines for applying various maintenance treatments are based on empirical observations of the pavement surface condition with time. This report presents the results of a comprehensive research effort to identify the optimum timing of surface treatment applications by providing a better understanding of the fundamental mechanisms that control the deterioration process of asphalt pavements. Both traditional and nontraditional pavement material characterization methods were carried out. The nontraditional methods consisted of X-Ray Photoelectron Spectroscopy (XPS) for quantifying aging, while for microcracks detection, electron microprobe imaging test (SEM) and fluorescent dyes for inspection of cracking were investigated. A new promising area, the spectral analysis of asphalt pavements to determine aging, was also presented. Traditional methods, such as Bending Beam Rheometer (BBR), Direct Tension (DTT), Dynamic Shear Rheometer (DSR) and Fourier Transform Infrared Spectroscopy (FTIR) for asphalt binders and BBR and Semi-Circular Bending (SCB) for mixtures were used to determine the properties of the field samples studied in this effort. In addition, a substantial analysis of measured pavement temperature data from MnROAD and simulations of pavement temperature using a one-dimensional finite difference heat transfer model were performed.
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    Environmental analysis of using recycled asphalt shingles in pavement applications.
    (2011-02) Austin, Jasmine
    Recycled asphalt shingles have been used in paving applications for more than two decades and have growing acceptance in the industry. The cost of asphalt binder has steadily increased, fueling pressure to find suitable recycled materials to supplement virgin materials. The Minnesota Department of Transportation has dedicated several studies for using asphalt shingle scrap in asphalt pavements. There are two types of shingles that can be used in pavement: manufacturer waste shingle scrap and tear off shingle scrap. As a result of the studies performed, the Minnesota Department of Transportation currently allows up to 5% of manufacturer waste shingle scrap in paving applications. Research on tear off shingle scrap is continuously developing, and a draft specification from the Minnesota Department of Transportation indicates that up to 5% can be used in asphalt pavement. In this thesis, both types of shingles were used in asphalt mixtures that were tested for performance to determine if the addition of shingles affects the physical properties. In addition, an environmental analysis was performed. The objective of this research was to determine if it physically makes sense to use shingles in pavement and to understand the environmental implications—which include reducing virgin materials which can yield energy savings. The analysis suggests up to 3% tear off shingle scrap in asphalt mixtures results in an effect on low temperature properties similar to the addition of up to 5% manufacturer waste shingle scrap, if combined with recycled asphalt pavement addition of more than 20%. The results of our research do support previous research efforts regarding the use of recycled asphalt shingles in pavement; however, based on these results, the Minnesota Department of Transportation draft specification for the use of tear off shingle scrap in asphalt pavement should state that up to 3%, not 5%, shingles can be used.
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    Investigation of Low Temperature Cracking in Asphalt Pavements National Pooled Fund Study 776
    (Minnesota Department of Transportation, 2007-10) Marasteanu, Mihai; Zofka, Adam; Turos, Mugur; Li, Xinjun; Velasquez, Raul; Li, Xue; Buttlar, William; Paulino, Glaucio; Braham, Andrew; Dave, Eshan; Ojo, Joshua; Bahia, Hussain; Williams, Christopher; Bausano, Jason; Gallistel, Allen; McGraw, Jim
    Good fracture properties are an essential requirement for asphalt pavements built in the northern part of the US and in Canada for which the predominant failure mode is cracking due to high thermal stresses that develop at low temperatures. Currently, there is no agreement with respect to what experimental methods and analyses approaches to use to investigate the fracture resistance of asphalt materials and the fracture performance of asphalt pavements. This report presents a comprehensive research effort in which both traditional and new experimental protocols and analyses were applied to a statistically designed set of laboratory prepared specimens and to field samples from pavements with well documented performance to determine the best combination of experimental work and analyses to improve the low temperature fracture resistance of asphalt pavements. The two sets of materials were evaluated using current testing protocols, such as creep and strength for asphalt binders and mixtures as well as newly developed testing protocols, such as the disk compact tension test, single edge notched beam test, and semi circular bend test. Dilatometric measurements were performed on both asphalt binders and mixtures to determine the coefficient of thermal contraction. Discrete fracture and damage tools were utilized to model crack initiation and propagation in pavement systems using the finite element method and TCMODEL was used with the experimental data from the field samples to predict performance and compare it to the field performance data.
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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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    Strength size effect in asphalt binders and mixtures at low temperature
    (2013-01) Cannone Falchetto, Augusto
    Low temperature cracking is the prevailing failure mode in asphalt pavements built in cold regions. This phenomenon manifests as a set of surface-initiated transverse cracks which can lead to further damage due to water penetration. Good strength properties of asphalt binders and asphalt mixtures are, therefore, critical for building durable pavements. The current testing methods used to characterize asphalt binder and mixture strength require the use of very expensive and sensitive testing devices and present limitations in the extrapolation of results from laboratory specimens to larger structures such as full scale pavements. In this thesis the strength size effect of asphalt materials is investigated with the aim of addressing the possibility of using a simple laboratory device, called Bending Beam Rheometer (BBR), for performing strength tests on small beam specimens of asphalt binders and asphalt mixtures. Using three-point bending experimental data and size effect theory for quasibrittle materials, the failure distribution of the Representative Volume Element (RVE) of asphalt binders and asphalt mixtures is evaluated, and a RVE substructure model for asphalt mixture is proposed to analyze the strength measurements obtained on small BBR beams. Forward and back calculation procedures are implemented to directly link the statistic parameters of failure distribution of one RVE to the mean size effect curve of structural strength and vice versa. The effect on strength of different cooling media used in BBR is also evaluated.