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Evaluation Of Asphalt Binder And Mixture Properties That Incorporate Reclaimed Asphalt Pavement
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Book Synopsis Evaluation of Asphalt Binder and Mixture Properties that Incorporate Reclaimed Asphalt Pavement by : Sang Ki Lee (M.S. in Engineering)
Download or read book Evaluation of Asphalt Binder and Mixture Properties that Incorporate Reclaimed Asphalt Pavement written by Sang Ki Lee (M.S. in Engineering) and published by . This book was released on 2018 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several private and public agencies are exploring ways in which the use of reclaimed asphalt pavement (RAP) can be increased in the construction of new pavements. However, such an increase must not come at the expense of reduced durability or life cycle cost. The use of RAP is often accompanied by some form of adjustment to the virgin binder that is being used. In Texas, the current practice of incorporating RAP is controlled by a simplified table that lists a substitute binder grade and recycled binder ratio (RBR) when RAP is incorporated in a mix. There are a few shortcomings with this simple approach of specifying a maximum ratio: (1) it does not address the potential difference in the quality of recycled binders from RAP, (2) it may result in the use of substituted binders with little or no polymer (elastomer) and (3) it does not account for the influence of recycling agents. The goal of this study was to evaluate the change in performance of binders and mixtures using different grades of virgin binder and percentages of RAP. Two different Job Mix Formulae (JMF) and corresponding materials were obtained from asphalt plants in the state of Texas. A test matrix was developed to evaluate binders and mixtures with different ratios of recycled binder to virgin binder and different ratios of RAP to virgin material, respectively. The results from this study show that addition of RAP or recycled binder (from RAP) results in an increase in stiffness and resistance to rutting, which was expected. However, the resistance to cracking showed mixed results. The test results also show that the properties of the recycled binder from RAP can vary significantly with source and have a drastic effect on the properties of the binder and mixture.
Book Synopsis Improved Mix Design, Evaluation, and Materials Management Practices for Hot Mix Asphalt with High Reclaimed Asphalt Pavement Content by : Randy Clark West
Download or read book Improved Mix Design, Evaluation, and Materials Management Practices for Hot Mix Asphalt with High Reclaimed Asphalt Pavement Content written by Randy Clark West and published by Transportation Research Board. This book was released on 2013 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB's National Cooperative Highway Research Program (NCHRP) Report 752: Improved Mix Design, Evaluation, and Materials Management Practices for Hot Mix Asphalt with High Reclaimed Asphalt Pavement Content describes proposed revisions to the American Association of State Highway and Transportation Officials (AASHTO) R 35, Superpave Volumetric Design for Hot Mix Asphalt, and AASHTO M 323, Superpave Volumetric Mix Design, to accommodate the design of asphalt mixtures with high reclaimed asphalt pavement contents.
Book Synopsis Simple Performance Tester for Superpave Mix Design by : Ramon Francis Bonaquist
Download or read book Simple Performance Tester for Superpave Mix Design written by Ramon Francis Bonaquist and published by Transportation Research Board. This book was released on 2003 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: The global response to COVID-19 has demonstrated the importance of vigilance and preparedness for infectious diseases, particularly influenza. There is a need for more effective influenza vaccines and modern manufacturing technologies that are adaptable and scalable to meet demand during a pandemic. The rapid development of COVID-19 vaccines has demonstrated what is possible with extensive data sharing, researchers who have the necessary resources and novel technologies to conduct and apply their research, rolling review by regulators, and public-private partnerships. As demonstrated throughout the response to COVID-19, the process of research and development of novel vaccines can be significantly optimized when stakeholders are provided with the resources and technologies needed to support their response. Vaccine Research and Development to Advance Pandemic and Seasonal Influenza Preparedness and Response focuses on how to leverage the knowledge gained from the COVID-19 pandemic to optimize vaccine research and development (R&D) to support the prevention and control of seasonal and pandemic influenza. The committee's findings address four dimensions of vaccine R&D: (1) basic and translational science, (2) clinical science, (3) manufacturing science, and (4) regulatory science.
Book Synopsis Engineered Frameworks for Evaluating the Use of Recycling Agents in Surface Asphalt Mixtures for Virginia by : Jhony Habbouche
Download or read book Engineered Frameworks for Evaluating the Use of Recycling Agents in Surface Asphalt Mixtures for Virginia written by Jhony Habbouche and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, several state highway agencies have introduced special provisions and specifications to allow the use of higher contents of reclaimed asphalt pavement (RAP) in asphalt surface mixtures. The challenges associated with high RAP mixtures can be addressed through the use of additives such as recycling agents (RAs) and/or softer binders. Currently, there are no specific guidelines or specifications available to evaluate the acceptability of RAs in Virginia. The purpose of this study was to evaluate the short- and long-term effectiveness of RAs in improving the performance of asphalt mixtures, particularly those with high RAP contents. Another objective of the study was to establish a performance-based framework to determine the acceptability of a specific RA product for inclusion in the Virginia Department of Transportation’s Approved Product List. Both objectives were achieved by benchmarking recycled binder blends (Phase I) and mixtures (Phase II). These were then compared in terms of laboratory performance to commonly used virgin asphalt binders and mixtures in Virginia. Moreover, a comprehensive review of the literature and information from state departments of transportation and RA suppliers on the current state of the practice regarding the use of recycled materials and RAs in asphalt mixtures was summarized. Component materials, including three virgin asphalt binders, RAP and aggregate materials from three different sources, and six RAs, were collected and tested. Phase I involved testing virgin and RAP binders; combinations of virgin binder and RAP binder; and combination of virgin binder, RAP binder, and RAs. A total of 26 binder blends were evaluated at various aging conditions through numerous rheology- and chemistry-based tests. In Phase II, 10 asphalt mixtures were designed and evaluated for durability, resistance to rutting, and resistance to cracking at various aging conditions. Cross-scale evaluation of asphalt binder and mixture testing data was established. Finally, preliminary verification was performed using data collected from various field trials constructed in Virginia. Based on the binders and mixtures tested in this study, the effectiveness of RAs in improving the properties of asphalt binder blends is specific to the product being used and to the targeted temperatures or conditions. Moreover, RAs can enhance the performance and increase the use of recycled materials in asphalt mixtures provided that the correct and suitable dosage of RA product is determined through a performance-based testing framework. The study recommends the following: (1) adopting the streamlined frameworks presented in this study to determine the acceptability of a given RA; (2) further validating the presented framework using different component materials; (3) employing balanced mix design tests to assess the performance characteristics of surface mixtures (with A and D designations) with RAs and drafting a roadmap; (4) collecting and further evaluating the field performance of all trials involving high RAP, RAs, and/or softer binders; (5) investigating the availability and activity of binders, especially with RAs, in RAP materials; (6) evaluating and establishing a protocol to assess the consistency of RAP materials; and (7) quantifying the environmental and economic impacts of using surface mixtures with high RAP contents and/or RAs.
Book Synopsis Superpave Mix Design by : Asphalt Institute
Download or read book Superpave Mix Design written by Asphalt Institute and published by . This book was released on 2001-01-01 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Laboratory Evaluation of Asphalt Concrete Mixtures Containing High Contents of Reclaimed Asphalt Pavement (RAP) and Binder by :
Download or read book Laboratory Evaluation of Asphalt Concrete Mixtures Containing High Contents of Reclaimed Asphalt Pavement (RAP) and Binder written by and published by . This book was released on 2014 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study investigated the effect of added asphalt binder content on the performance and volumetric properties of asphalt concrete mixtures containing reclaimed asphalt pavement (RAP) in the amounts of 0%, 20%, and 40%. A laboratory-produced mixture containing 100% RAP was also evaluated. Performance of the mixtures was evaluated based on three criteria: stiffness (dynamic modulus), fatigue resistance, and rutting resistance (flow number and asphalt pavement analyzer). Results showed that a 0.5% increase in binder content improved both the fatigue and rutting resistance of the 0% and 20% RAP mixtures with only slight (insignificant) decreases in dynamic modulus. However, the addition of various amounts of binder to the 40% RAP mixture led to a significant decrease in rutting resistance with little or no improvement to fatigue resistance. Volumetric analysis was performed on all of the mixtures, and detailed results are presented. Based on the results of the study, the authors recommend that the Virginia Department of Transportation supplement current asphalt mixture design procedures that are based on mixture volumetric properties with laboratory-mixture performance testing.
Book Synopsis Evaluation of Reclaimed Asphalt Pavement for Surface Mixtures by : Rebecca McDaniel
Download or read book Evaluation of Reclaimed Asphalt Pavement for Surface Mixtures written by Rebecca McDaniel and published by Purdue University Press. This book was released on 2012-08-01 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Indiana Department of Transportation has successfully used Reclaimed Asphalt Pavement (RAP) for decades because of its economic and environmental benefits. Because of uncertainties regarding the types of aggregates contained in RAP and their resulting frictional properties, INDOT has until recently disallowed the use of RAP in asphalt surface mixtures. In addition, the hardened asphalt binder in the RAP could potentially increase the occurrence of thermal cracking. This research was conducted to explore the effects on RAP with poor or unknown aggregate qualities to establish maximum allowable RAP contents to provide adequate friction. The effects of RAP on thermal cracking were then investigated at the potential allowable RAP contents. Laboratory testing showed that the addition of poor quality RAP materials did impact the frictional properties and cracking resistance of the mixtures, but that lower amounts of RAP had little effect. The frictional performance of the laboratory fabricated and field sampled RAP materials was acceptable at contents of 25% but may be questionable at 40%. Field friction testing was also conducted on existing roadways with RAP to explore their field frictional performance. Several low volume roadways and one experimental interstate project were tested. The field results showed acceptable performance after 3 to 5 years of low volume traffic at RAP contents of 15-25% and after more than 10 years of interstate traffic with 15% RAP. Low temperature testing showed an increased susceptibility to thermal cracking as the RAP content increased but the change in critical cracking temperature was relatively small at the 25% RAP level. At 40% RAP without a change in the virgin binder grade, the critical cracking temperature was about 6 C warmer than the control mixture. This finding supports the need for a binder grade change for RAP contents greater than 25%, as indicated in other research and as required by the current INDOT specifications.
Download or read book Hot-mix Asphalt Mixtures written by and published by . This book was released on 1999 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios by : Amy Epps Martin
Download or read book Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios written by Amy Epps Martin and published by . This book was released on 2020 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: "More than 90 percent of highways and roads in the United States are built using hot-mix asphalt (HMA) or warm-mix asphalt (WMA) mixtures, and these mixtures now recycle more than 99 percent of some 76.2 million tons of reclaimed asphalt pavement (RAP) and about 1 million tons of recycled asphalt shingles (RAS) each year. Cost savings in 2017 totaled approximately $2.2 billion with these recycled materials replacing virgin materials. The TRB National Cooperative Highway Research Program's NCHRP Research Report 927: Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios presents an evaluation of how commercially available recycling agents affect the performance of asphalt mixtures incorporating RAP and RAS at high recycled binder ratios."--
Author :National Research Council (U.S.). Transportation Research Board Publisher :Transportation Research Board National Research ISBN 13 : Total Pages :64 pages Book Rating :4.:/5 (359 download)
Book Synopsis Recycling Materials for Highways by : National Research Council (U.S.). Transportation Research Board
Download or read book Recycling Materials for Highways written by National Research Council (U.S.). Transportation Research Board and published by Transportation Research Board National Research. This book was released on 1978 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This synthesis will be of special interest and usefulness to design engineers, materials technologists, and others seeking information on the potential use of recycled materials in design, construction, rehabilitation, and maintenance of pavements, bases, and other components of the highway system. Detailed information is presented on procedures for pavement recycling."--Avant-propos.
Book Synopsis Reclaimed Asphalt Pavement by : Imad L. Al-Qadi
Download or read book Reclaimed Asphalt Pavement written by Imad L. Al-Qadi and published by . This book was released on 2007 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Illinois has been recycling Reclaimed Asphalt Pavement (RAP) material into hot-mix asphalt (HMA) since 1980, this research project seeks to determine the appropriate level of contribution that should be given to the residual asphalt binder in RAP.
Book Synopsis Improved Mix Design, Evaluation, and Materials Management Practices for Hot Mix Asphalt with High Reclaimed Asphalt Pavement Content by : Randy Clark West
Download or read book Improved Mix Design, Evaluation, and Materials Management Practices for Hot Mix Asphalt with High Reclaimed Asphalt Pavement Content written by Randy Clark West and published by . This book was released on 2013 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB's National Cooperative Highway Research Program (NCHRP) Report 752: Improved Mix Design, Evaluation, and Materials Management Practices for Hot Mix Asphalt with High Reclaimed Asphalt Pavement Content describes proposed revisions to the American Association of State Highway and Transportation Officials (AASHTO) R 35, Superpave Volumetric Design for Hot Mix Asphalt, and AASHTO M 323, Superpave Volumetric Mix Design, to accommodate the design of asphalt mixtures with high reclaimed asphalt pavement contents.
Book Synopsis Fundamental Evaluation of the Interaction Between RAS/RAP and Virgin Asphalt Binders by : Munir D. Nazzal
Download or read book Fundamental Evaluation of the Interaction Between RAS/RAP and Virgin Asphalt Binders written by Munir D. Nazzal and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive laboratory testing program was conducted in this research project to examine the blending between reclaimed asphalt pavement (RAP)/recycled asphalt shingles (RAS) and virgin asphalt binders and to evaluate the factors that may affect fatigue and low-temperature cracking as well as moisture-induced damage in asphalt mixtures prepared using these materials. This project included two parts: a binder study and a mixture study. In the binder study, atomic force microscopy (AFM) was utilized to characterize the micromechanical properties of the interfacial zone that develops between the RAP/RAS binders and the virgin asphalt binders. Three virgin asphalt binders with different performance grades (PG 58-28, PG 64-28, and PG 64-22), three RAP sources, as well as manufacturing waste and tear-off RAS were used in this project. A new sample-preparation procedure was developed to simulate the blending between the RAS/RAP and the virgin asphalt binders that occurs during asphalt mixture production. The micro-structure, stiffness and the adhesive properties along the blending zone were evaluated for different combinations of RAP/RAS binders and virgin binders. In the mixture study, several asphalt mixtures were used to evaluate the effect of the incorporation of RAP and/or RAS on the mix performance, including a control mixture (no RAP or RAS), a mixture containing 30% RAP, a mixture containing 5% tear-off RAS, and a mixture containing 20% RAP and 3% tear-off RAS. All mixtures were designed to meet ODOT specifications for Item 442 (Superpave) Type A for heavy traffic intermediate course asphalt mixes. The resistance of the asphalt mixtures to fatigue cracking was evaluated using the semi-circular bend (SCB) and the indirect tensile strength (IDT) tests. The SCB test was performed using the Illinois Method and the Louisiana Method. In addition the potential for low-temperature cracking was evaluated using the asphalt concrete cracking device (ACCD), and the susceptibility of the asphalt mixtures to moisture-induced damage was evaluated using the AASHTO T 283 (modified Lottman) test. The AFM test results indicated that blending occurred to a varying degree between the RAP binders and the virgin binders for all RAP-virgin binder combinations. The average modulus of the blending zone depended on the properties of the RAP and the virgin binders. For all binders, a reduction in the adhesive bonding energy was also observed in the blending zone due to the presence of RAP. However, the adhesive properties of the blending zone were significantly higher than those in the RAP binders. Statistical analysis also indicated that the stiffness of the interface blending zone is affected by the properties of the RAP and virgin asphalt binders, while the adhesive properties of the interface blending zone is primarily affected by those of virgin binder used. A linear regression model was developed to predict the modulus and adhesive bonding energy of the blending zone in terms of RAP and virgin binder properties. The validation of the regression models suggested that these models can serve as a viable tool in selecting the virgin binder to be used in a RAP mixture based on the properties of the RAP binder. Finally, the AFM imaging and force spectroscopy experiments revealed very limited to no blending between manufacturing waste or tear-off RAS materials and the virgin binders considered. The asphalt mixture test results also showed that the use of tear-off RAS in intermediate asphalt mixes significantly reduced their resistance to low-temperature and fatigue cracking as well as moisture damage, which can be attributed to the limited blending observed in the AFM experiments between the RAS and the virgin asphalt binders.
Book Synopsis Performance Assessment of Asphalt Mixes Containing Reclaimed Asphalt Pavement and Tire Rubber by : Shawn Shiangfeng Hung
Download or read book Performance Assessment of Asphalt Mixes Containing Reclaimed Asphalt Pavement and Tire Rubber written by Shawn Shiangfeng Hung and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The pavement community, including both agencies and industries, is moving toward more sustainable pavement designs and pavement network management. Increasing amounts of recycled materials, both reclaimed asphalt pavement (RAP) and recycled tire rubber, are expected to be used in new pavement construction projects in the future to reduce the use of virgin binder and aggregates. The main concern of using recycled materials in new asphalt pavement is the potential negative effect on the performance. Thus, the primary objective of this dissertation is to improve the current laboratory testing technologies and performance assessment approaches for characterizing the performance-related properties of asphalt mixes containing recycled materials and to improve understanding of how these properties affect the performance of asphalt pavements so that they can be designed and constructed better. A major challenge regarding the use of high RAP content mixes is the differences in the rheological properties of the virgin binder (mixes without RAP) and the blended binder (mixes with RAP). Traditionally, binder blending charts are used to determine the appropriate RAP content in asphalt mixes and the selection of virgin binder grade as part of the Superpave volumetric mix design procedures when RAP is incorporated in the mix. However, producing mixes based on blending charts that require testing of extracted and recovered RAP binders is expensive and hazardous. An alternative test approach for binder blending charts using fine aggregate matrix (FAM) mix testing is presented in this dissertation. The results demonstrated that the proposed approach could estimate the blended binder intermediate and low performance grading temperatures within ±3°C of the measured blended binder performance grading temperatures. Even though the proposed approach is not as accurate as the blending chart method (within ±2°C), it provides both cost and environmental benefits. Currently, the Superpave Performance Grading (PG) system cannot not be used to evaluate the performance-related properties of asphalt rubber binders produced using larger crumb rubber particles (maximum particle size passing 2.36 mm sieve) due to the limitations of parallel plate geometry. With the consideration of more open-graded or gap-graded rubberized hot mix asphalt (RHMA-O and RHMA-G) projects in the future, it is important to be able to perform Superpave PG testing on asphalt rubber binder and to establish performance-based contract acceptance criteria for the production of asphalt rubber binders. The test results indicated that the concentric cylinder geometry is an appropriate alternative geometry to parallel plates for quantifying the properties of asphalt rubber binders and specifically for assessing the high-temperature performance properties of binders containing crumb rubber particles larger than 250 [mu]m. Concerns have been raised with regard to incorporating reclaimed rubberized asphalt pavement (RRAP) into dense-graded new hot mix asphalt (HMA-DG) and RAP into new RHMA-G since the interactions between the virgin binder, age-hardened binder, and recycled tire rubber could considerably affect the rutting, fatigue cracking, and thermal cracking performances of new HMA-DG and RHMA-G. The fundamental differences between RAP and RRAP were identified and the performance of new mixes that contain these recycled materials were evaluated in this study. The experimental results showed that adding RRAP to HMA-DG mixes is ideal to resist rutting and low-temperature cracking based on the changes in mix stiffness. The HMA-DG mixes containing RRAP are better at resisting high tensile strain loadings than mixes containing RAP. In addition, adding RAP to RHMA-G mixes improves the rutting performance but diminishes the cracking performance, and potentially negating the benefits of selecting RHMA-G as an overlay to retard the rate of reflection cracking. Lastly, the effects of rest periods on asphalt fatigue performance considering asphalt thixotropy, non-linearity, self-heating, self-cooling, and steric hardening were also investigated in this research. The experimental test results showed that asphalt thixotropic softening and other biasing effects control the first 10 to 15 percent decrease in stiffness for unmodified binders and 15 to 35 percent decrease in stiffness for modified binders under cyclic loading, and this decrease in stiffness can be recovered with the introduction of rest periods. This means that most of the repeated loadings applied to test specimens within the thixotropic softening range do not caused any fatigue damage but only softening of the materials. Thus, by providing sufficient rest periods within the thixotropic softening range can effectively improve asphalt fatigue performance. Both the thixotropic softening range and the required time for thixotropic recovery (i.e., rest periods) need to be considered in asphalt fatigue test and mechanistic-empirical (ME) design for better evaluation of the true fatigue performance.
Book Synopsis Characterization of Asphalt Mixtures and Rap Binder Properties Through Impact Resonance Test by : Ilker Boz
Download or read book Characterization of Asphalt Mixtures and Rap Binder Properties Through Impact Resonance Test written by Ilker Boz and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Characterization of asphalt concrete is of paramount importance for the sound structural design and analysis of flexible pavements. Of equal importance is the availability of test methods that can provide an accurate and reliable measure of the required engineering properties of the material. For routine applications in material characterization, selected test methods should be reliable, simple, quick, repeatable, and cost eective. The use of nondestructive test (NDT) methods has proven to provide such characterization capabilities. Among those methods, the impact resonance (IR) test is a vibration based NDT method, and has been increasingly used for asphalt concrete evaluation and characterization in the past two decades. The majority of studies regarding the IR test in asphalt concrete applications have been focused on comparison of the IR test moduli with the moduli obtained from conventional asphalt concrete dynamic modulus tests and the predictive equations. In this dissertation, the IR test was utilized to characterize the properties of asphalt concrete mixtures and recycled asphalt pavement (RAP) binder through mixture testing at a range of temperatures. To this eect, several independent studies were conducted.The second order equation of motion assumption in rheological modeling of the IR test response was evaluated for asphalt concrete testing. A set of asphalt concrete specimens was tested with the IR test, and the obtained signals at a range of temperatures were evaluated by means of the Hankel matrix method. The results showed that the assumption is violated for asphalt concrete testing, especially at high temperatures, mainly due to the presence of noise in the obtained response. However, the Hankel method was employed to filter out the noise. It was seen that the assumption could be employed for asphalt concrete at a range of temperatures including high temperatures, provided that the filtering is performed on the obtained signal. The results also showed that the employed filtering procedure produced improvements for the IR test material dependent responses, resonant frequency and especially damping ratio calculations.The IR test results are influenced by specimen size and testing configurations. A study was conducted to investigate the influence of aspect ratio (length/diameter) of laboratory specimens on the frequency response of asphalt concrete when tested with the IR. The IR test, performed in a longitudinal mode, demonstrated that the test is repeatable and reproducible. The test results indicated that the frequency response increased as the aspect ratio increased approximately up to 0.7, and then it decreased with a nonlinear trend as the aspect ratio increased beyond 0.7, indicating that the tendency of the frequency response reached a plateau as the aspect ratio increased. It was inferred from the test results that there was a threshold aspect ratio at which the fundamental longitudinal frequency mode was not the dominant frequency mode. Velocity calculations from measured resonant frequencies indicated that the true material properties for the longitudinal mode could be attained at an aspect ratio of as low as 1.In another study, the sensitivity of the resonant frequency response of the IR testing of asphalt concrete to asphalt concrete mixture parameters was investigated. The IR tests were performed on disk-shaped asphalt concrete specimens at the transverse (flexural) mode of vibration at a temperature range of approximately -10 to 50oC. Test results revealed that the relationship between the resonant frequency and temperature was described by a polynomial fit, and it was shown through statistical analysis that the slopes of the fit were significantly aected by mixture parameters such as air void content and binder content. Also, the statistical formulation (predictive model) between the resonant frequency and the asphalt concrete mixture parameters were established for a given aggregate gradation of nominal maximum size and an aggregate specific gravity. The prediction accuracy of the model was evaluated by independent data sets, and the test results indicated that the maximum error between the measured and predicted resonant frequencies was not more than 9 percent.In an eort to characterize the properties of recycled asphalt pavement (RAP) binder with the IR test through asphalt concrete mixture testing, two approaches were utilized. An approach is proposed for determination of binder properties through the IR testing of mixtures with RAP and binders with known engineering properties. The IR tests were performed in the longitudinal mode at a range of temperatures between 3 and 35oC. Also, RAP binder and virgin binders were tested using dynamic shear rheometer (DSR) at the same temperature range as the IR testing. It was seen that the IR test ranked the expected trend of binder stiness with respect to the resonant frequency of mixtures. The results indicate the potential of the proposed concept and feasibility of the approach in determining binder properties, including properties of the RAP binder. A practical method is proposed for determination of binder properties based on mixture testing.In the second approach, the IR test potential to characterize the low-temperature properties of an RAP binder that incorporated a rejuvenating agent was investigated. This approach included testing of mixes with virgin binders and pure RAP mixes treated with a rejuvenating agent at dierent levels using the IR, as well as testing of blends of recovered RAP binder, rejuvenator, and virgin binder using bending beam rheometer (BBR). The results showed that the IR test can properly rank the expected stiness of binders through mixture testing. The results also indicated high linear correlations between mixture properties obtained from the IR test (modulus and phase angle) and binder properties obtained from the BBR test (stiness and m-value, a relaxation index). The results clearly demonstrate the potential of IR to be used for grading and optimization for the asphalt binder of RAP and rejuvenator content in lieu of the binder recovery method.
Book Synopsis Fatigue and Stiffness Evaluations of Reclaimed Asphalt Pavement in Hot Mix Asphalt Mixtures by : Feipeng Xiao
Download or read book Fatigue and Stiffness Evaluations of Reclaimed Asphalt Pavement in Hot Mix Asphalt Mixtures written by Feipeng Xiao and published by . This book was released on 2011 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The recycling of existing asphalt pavement materials produces new pavements with considerable savings in material, money, and energy. Understanding the ability of an asphalt pavement containing reclaimed asphalt pavement (RAP) to resist fracture from repeated loads is essential for the design of hot mix asphalt (HMA) mixtures. However, reaching a better understanding of fatigue behaviors of these pavements continues to challenge researchers all over the world, particularly, as recycled materials with more complex properties are being used in HMA pavements. This study explores the utilization of the conventional fatigue analysis approach in investigating the fatigue life of asphalt mixtures containing RAP. The fatigue beams were made with two asphalt binders, two aggregate sources, four RAP contents (0 %, 15 %, 25 %, and 30 %), and tested at 5 and 20°C. A total of eight mixtures was evaluated and 64 fatigue beams were tested in this study. The test results indicated that the addition of RAP, as expected, increased the viscosity, G*sin?, and creep stiffness values while reducing the m-values. However, no obvious trends were found for stiffness and fatigue life of mixtures as the RAP content increased. Statistical analysis results indicated that for binders and mixtures containing 30 % RAP, the utilization of softer binder significantly decreased the viscosity, G*sin?, and creep stiffness values; however, there were no significant differences in the stiffness and fatigue life values of these mixtures.
Book Synopsis Physical Properties of Asphalt Cement Binders by : John C. Hardin
Download or read book Physical Properties of Asphalt Cement Binders written by John C. Hardin and published by ASTM International. This book was released on 1995 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: A dozen papers from a December 1993 symposium in Dallas/Fort Worth, Texas. Among the topics are why the new proposed rheological properties of asphalt binders are required and how they compare to conventional properties, the development and use of the SHRP direct tension specification test, oxidatio
