Download or read book Evaluation of the Effects of Asphalt Binder on the Properties of Hot Mix Asphalt at Intermediate Temperatures written by Haifang Wen and published by . This book was released on 2011 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The asphalt binder is an essential component of asphaltic mixtures. The performance of an asphaltic mixture is directly related to mechanical characteristics of the binder. With the development of new material characterization methods for both asphalt binder and asphaltic mixture, there is a need to re-evaluate the relationship between the properties of binders and asphaltic mixtures such that a proper understanding and selection of an asphalt binder can be made to improve the performance of an asphaltic mixture. In this study, the effects of asphalt binder properties on asphaltic mixtures at intermediate temperatures were evaluated based on recent developments on material characterization methods for both binder and asphaltic mixture. Five asphalt binders and five asphalt mixtures containing these binders with one aggregate were tested. Four of the binders were based on a modification of a base binder with different techniques. Complex shear modulus and monotonic constant shear-rate tests were conducted on asphalt binders, whereas dynamic modulus and indirect tensile strength tests were conducted on the mixtures. The effects of modification techniques on the properties of asphalt binders and the relationships between the properties of binders and asphaltic mixtures were evaluated in this study.
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.
Download or read book Significant Findings from Full scale Accelerated Pavement Testing written by Wynand JvdM. Steyn and published by Transportation Research Board. This book was released on 2012 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: "TRB's National Cooperative Highway Research Program (NCHRP) Synthesis 433: Significant Findings from Full-Scale Accelerated Pavement Testing documents and summarizes significant findings from the various experimental activities associated with full-scale accelerated pavement testing (f-sAPT) programs that have taken place between 2000 and 2011. The report also identifies gaps in knowledge related to f-sAPT and where future research may be needed. NCHRP Synthesis 433 is designed to expand the f-sAPT base of knowledge documented in NCHRP Syntheses 325 and 235, both with the same title of Significant Findings from Full-Scale Accelerated Pavement Testing. f-sAPT is the controlled application of a wheel loading, at or above the appropriate legal load limit, to a pavement system to determine pavement response in a compressed time period. The acceleration of damage is achieved by one or more of the following factors: increased repetitions, modified loading conditions, imposed climatic conditions, and thinner pavements with a decreased structural capacity which have shorter design lives"--
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.
Download or read book Evaluation of Short Term Aging Effect of Hot Mix Asphalt Due to Elevated Temperatures and Extended Aging Time written by Rubben Lolly and published by . This book was released on 2013 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heating of asphalt during production and construction causes the volatilization and oxidation of binders used in mixes. Volatilization and oxidation causes degradation of asphalt pavements by increasing the stiffness of the binders, increasing susceptibility to cracking and negatively affecting the functional and structural performance of the pavements. Degradation of asphalt binders by volatilization and oxidation due to high production temperature occur during early stages of pavement life and are known as Short Term Aging (STA). Elevated temperatures and increased exposure time to elevated temperatures causes increased STA of asphalt. The objective of this research was to investigate how elevated mixing temperatures and exposure time to elevated temperatures affect aging and stiffening of binders, thus influencing properties of the asphalt mixtures. The study was conducted in two stages. The first stage evaluated STA effect of asphalt binders. It involved aging two Performance Graded (PG) virgin asphalt binders, PG 76-16 and PG 64-22 at two different temperatures and durations, then measuring their viscosities. The second stage involved evaluating the effects of elevated STA temperature and time on properties of the asphalt mixtures. It involved STA of asphalt mixtures produced in the laboratory with the PG 64-22 binder at mixing temperatures elevated 25OF above standard practice; STA times at 2 and 4 hours longer than standard practices, and then compacted in a gyratory compactor. Dynamic modulus (E*) and Indirect Tensile Strength (IDT) were measured for the aged mixtures for each temperature and duration to determine the effect of different aging times and temperatures on the stiffness and fatigue properties of the aged asphalt mixtures. The binder test results showed that in all cases, there was increased viscosity. The results showed the highest increase in viscosity resulted from increased aging time. The results also indicated that PG 64-22 was more susceptible to elevated STA temperature and extended time than the PG 76-16 binders. The asphalt mixture test results confirmed the expected outcome that increasing the STA and mixing temperature by 25oF alters the stiffness of mixtures. Significant change in the dynamic modulus mostly occurred at four hour increase in STA time regardless of temperature.
Download or read book Asphalt Pavements written by Patrick Lavin and published by CRC Press. This book was released on 2003-09-02 with total page 463 pages. Available in PDF, EPUB and Kindle. Book excerpt: Asphalt Pavements provides the know-how behind the design, production and maintenance of asphalt pavements and parking lots. Incorporating the latest technology, this book is the first to focus primarily on the design, production and maintenance of low-volume roads and parking areas.Special attention is given to determining the traffic capacity, re
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
Download or read book Proceedings of the 10th International Conference on Maintenance and Rehabilitation of Pavements written by Paulo Pereira and published by Springer Nature. This book was released on with total page 643 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interaction Between New and Age hardened Binders in Asphalt Mixes Containing High Quantities of Reclaimed Asphalt Pavement and Reclaimed Asphalt Shingles written by Yuan He and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As virgin pavement material sources become scarcer and costlier the use of higher quantities of reclaimed asphalt pavement (RAP) and reclaimed asphalt shingles (RAS) in the production of new asphalt mixes becomes increasingly desirable. RAP/RAS binder in the mix has different levels of aging. Through oxidation, the binder becomes stiffer and more rigid than virgin binder, and thus results in a pavement material that is more brittle and susceptible to fatigue and thermal cracking. The purpose of this dissertation study was to investigate the interactions between new and age binders and evaluate asphalt mixes performance. A major concern associated with the use of high percentages of RAP and/or RAS is the level of blending between virgin and age-hardened binders, because the performance of the mix can be highly influenced by the properties of the composite binder. The blending between new binder and age-hardened RAP binder can be explained through diffusion mechanisms. This research used asphalt binder testing and diffusion and aging theory to investigate the evolution of blending between virgin and RAP binders during asphalt mix production, storage, and placement. The rheological properties of a two-layer asphalt binder sample composed of virgin and simulated RAP binder were measured using a dynamic shear rheometer (DSR) after conditioning following hot mix asphalt (HMA) and warm mix asphalt (WMA) time-temperature paths during mixing and placement. The diffusion and aging coefficients for the composite binder were estimated by comparing measured shear stiffness values with those predicted using a diffusion model and considering asphalt binder aging over time. The diffusion model is solved numerically based on the finite control volume approach. Results show that the HMA results in nearly full blending of the new and aged binders following the time-temperature paths used in this study; while the WMA results in only partial blending. Traditionally, the properties of blended binders in asphalt mixes containing RAP and RAS are evaluated through rheological testing of the binder extracted and recovered from a mix. However, this approach has long been criticized for being labor intensive, for potentially altering the chemistry of the binder and consequently changing the binder rheology, for forcing blending of binders that may not have been present in the mix, and for creating hazardous material disposal issues. The research presented in this dissertation proposes an alternative approach for characterizing blended binders by testing the linear viscoelastic properties of a fine aggregate matrix (FAM) asphalt mix using a torsion bar fixture in a DSR. A procedure has been developed for preparation and testing of small FAM cylindrical FAM specimens. The results demonstrated that this testing is sensitive to FAM mixes made of different virgin binders, RAP/RAS contents, with and without rejuvenating agent. More importantly, FAM mix testing shows similar results as that from DSR binder testing and full mix testing in terms of rankings of master curves and Black diagrams. Statistical analysis (ANOVA) on stiffness values from FAM testing also provides the same conclusion to that at binder and mix levels. Therefore, FAM approach has the potential to be used as a substitute to stiffness testing for mix comparison purposes. It is also a less expensive and more efficient testing approach than the full mix testing.The combined effect of RAP, RAS, and different virgin binder sources and grades on performance of the blended binders and asphalt mixes was also investigated. Previous studies have indicated that RAP, RAS, and virgin binder grades each has certain effects on performance of the mix. The addition of RAP/RAS undermines fatigue and thermal performance and improves rutting resistance. The virgin binder grade should be carefully chosen based on the percentages of RAP/RAS in the mix. Results from unconfined RLT appears to show that reducing the binder grade when using more than 25 percent RAP results in rutting performance similar to the original grade. Therefore, it is likely safe for high temperatures if the binder grade is reduced to meet the low and intermediate temperature requirements. Asphalt binders contain different organic molecules, and thus their chemical compositions vary according to the source of the oil used in their production. Virgin binders from different sources blend differently with the age-harden oxidized binder in RAP/RAS. Therefore, depending on the level of blending between virgin and oxidized binders, the performance of the mixes could vary substantially. Findings from this work indicated that virgin binder source had some effect on the blended materials. Additional research that came from the testing approaches to complete the investigation of RAP/RAS with this dissertation were also investigated. All the asphalt mixes used in this study were designed following Caltrans modified Superpave mix design procedure and tested using an Asphalt Mixture Performance Tester (AMPT). The effects of specimen preparation variables in terms of compaction method, compaction level, test temperature, stress state, and deformation measurement location when using the AMPT to predict mix stiffness and permanent deformation were evaluated. The best approach using Superpave testing equipment that appears to best characterize expected rutting performance as defined by previous calibrated RSCH results were also investigated.
Download or read book Introduction to Unmanned Aircraft Systems Second Edition written by Douglas M. Marshall and published by CRC Press. This book was released on 2015-10-26 with total page 1944 pages. Available in PDF, EPUB and Kindle. Book excerpt: The proliferation of technological capability, miniaturization, and demand for aerial intelligence is pushing unmanned aerial systems (UAS) into the realm of a multi-billion dollar industry. This book surveys the UAS landscape from history to future applications. It discusses commercial applications, integration into the national airspace system (NAS), System function, operational procedures, safety concerns, and a host of other relevant topics. The book is dynamic and well-illustrated with separate sections for terminology and web- based resources for further information.
Download or read book Validating the Fatigue Endurance Limit for Hot Mix Asphalt written by Brian D. Prowell and published by Transportation Research Board. This book was released on 2010 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: At head of title: National Cooperative Highway Research Program.
Download or read book Binder Characterization and Evaluation Test methods written by and published by . This book was released on 1994 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the RILEM International Symposium on Bituminous Materials written by Hervé Di Benedetto and published by Springer Nature. This book was released on 2021-09-25 with total page 1806 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume highlights the latest advances, innovations, and applications in bituminous materials and structures and asphalt pavement technology, as presented by leading international researchers and engineers at the RILEM International Symposium on Bituminous Materials (ISBM), held in Lyon, France on December 14-16, 2020. The symposium represents a joint effort of three RILEM Technical Committees from Cluster F: 264-RAP “Asphalt Pavement Recycling”, 272-PIM “Phase and Interphase Behaviour of Bituminous Materials”, and 278-CHA “Crack-Healing of Asphalt Pavement Materials”. It covers a diverse range of topics concerning bituminous materials (bitumen, mastics, mixtures) and road, railway and airport pavement structures, including: recycling, phase and interphase behaviour, cracking and healing, modification and innovative materials, durability and environmental aspects, testing and modelling, multi-scale properties, surface characteristics, structure performance, modelling and design, non-destructive testing, back-analysis, and Life Cycle Assessment. The contributions, which were selected by means of a rigorous international peer-review process, present a wealth of exciting ideas that will open novel research directions and foster new multidisciplinary collaborations.
Download or read book Case Study written by Shenghua Wu and published by . This book was released on 2018 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current experimental methods for the extraction and recovery of asphalt binder from asphalt mixtures were designed for hot mix asphalt (HMA); however, it was not ascertained whether or not these methods could also be used for warm mix asphalt (WMA). There are concerns about the inability of current methods to fully extract and recover WMA additives from WMA mixtures, such as Sasobit wax, that can crystallize at room. Therefore, this study investigated the effectiveness of current HMA binder extraction methods for WMAs containing Sasobit additive. An experimental program was designed to evaluate the effect of extraction temperature. The loose mixes for HMA and Sasobit were prepared and subjected to three different aging levels (2hours, 15hours, and 5 days) and were extracted at an intermediate temperature (25°C) and an elevated temperature (80°C), respectively. Sasobit can be extracted at 80°C, which was confirmed by the results from the rheological properties test (performance grading, multiple stress creep and recovery test, and frequency sweep test) and a chemical analysis test (Fourier transform infrared spectroscopy test) for the HMA- and Sasobit-extracted binders. Four field Sasobit WMA projects further verified the feasibility of an 80°C extraction temperature for the Sasobit binder. It was also found in this study that the effect of Sasobit on the base binders became less significant after it was subjected to long-term aging in the field.
Download or read book Evaluation of Warm Mix Asphalt Technologies with Respect to Binder Aging and Emissions written by Faramarz Farshidi and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years Warm Mix Asphalt (WMA) technologies have been used to modify asphalt binders, with the following objectives: to decrease production and construction temperatures, reduce fumes and emissions, increase haul distance, and improve the workability of the mix. Reduced temperatures at the plant and during laydown and compaction are hypothesized to positively impact long-term oxidative aging behavior due to less oxidation/aging and result in less emissions during production and construction due to reduced production and construction temperatures. The purpose of this investigation was to quantify these improvements with respect to long-term oxidative aging in the field and environmental benefits with respect to volatile organic compounds, semi-volatile organic compounds and poly cyclic aromatic hydrocarbons in order to confirm or deny this hypothesis. This research evaluated the potential durability of WMA and Rubberized Warm Mix Asphalt (R-WMA) binders with respect to long-term aging through characterization of field-aged binders extracted and recovered from field cores. The results were compared to the control conventional Hot Mix Asphalt (HMA) and Rubberized Hot Mix Asphalt (R-HMA) samples. Binders were extracted and recovered from thirteen different test sections and a total of seven different WMA technologies were evaluated in this study. The Dynamic Shear Rheometer (DSR) was used to evaluate the rheological properties of the binders at high temperatures with respect to rutting performance in the field. The Bending Beam Rheometer (BBR) was used to characterize low temperature properties of the binder samples. A new testing procedure was developed to measure and characterize the rheological properties of the R-HMA and R-WMA binders with respect to performance-related properties in the field. The rheological results indicated that depending on the WMA technology used, the addition of WMA technologies and reduced production and compaction temperatures result in increase or decrease rutting resistance performance for WMA and R-WMA binders with respect to permanent deformation at high temperatures in the field. Both WMA and R-WMA binders studied meet the established thermal cracking criteria with respect to low temperature cracking in the field. The aging kinetics curves for WMA-treated binders are parallel to the control binders and the addition of WMA technologies including organic, chemical and mechanical foaming technologies studied in this research did not result in a different aging kinetics trend with respect to long-term aging in the field. A portable "flux" chamber was designed and fabricated to capture and directly measure emissions during paving operations. Emissions were collected in activated charcoal sorbent tubes for characterizing volatile organic compounds and semi-volatile organic compounds. XAD-2 resin tubes and filters were used to capture the gaseous phase and particulate phase of the PAH compounds, respectively. A reliable analytical method was developed to identify and quantify alkane emissions using gas chromatography mass spectrometry (GC/MS) in the laboratory. A separate method was developed for identification and characterization of trace level PAH compounds of the asphalt fumes. The results demonstrated that the warm mix asphalt technology type, plant mixing temperature and level of compaction significantly influence the emission characteristics throughout paving operations. Moreover, the emissions kinetics indicated that the majority of the reactive organic gases are volatilized in the first hour after sampling initiation (immediately after production and before compaction). To better understand and identify any chemical composition changes of the binder due to WMA technologies, nuclear magnetic resonance spectroscopy (NMR) was used for understanding structural complexities of HMA and WMA binder molecules. Qualitative analysis of both carbon and hydrogen atoms with HMA and WMA binders showed that the molecular structures of the binders are not significantly changed by the effect of WMA technologies.
Download or read book A Manual for Design of Hot Mix Asphalt with Commentary written by and published by Transportation Research Board. This book was released on 2011 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantifying the Impacts of Warm Mix Asphalt on Constructability and Performance written by and published by . This book was released on 2012 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: Joint efforts by the federal government and HMA industry to minimize cost and the environmental impacts of asphalt pavement construction have resulted in development of warm mix asphalt (WMA). This technology has gained such interest due to the potential to deliver pavements at lower temperatures, allowing for reduced energy consumption and emissions. In order to be effective WMA must meet the specified values of in-place density at reduced temperatures during construction and demonstrate sufficient resistance to pavement distresses while in-service. The overall objective of this research was to promote effective use of WMA through development of a procedure to recommend additive specific mixing and compaction temperature ranges that will provide adequate workability during construction, and an acceptable level of in-service performance. To pursue this objective an experiment was designed to evaluate the effects of various WMA technologies on the workability and performance properties of asphalt binders and mixtures using existing standards and new test methods developed during the study. The new test methods were pursued to better define the role of asphalt binder as a lubricant during compaction and to properly account for the effects of reduced production temperatures on asphalt binder performance and potential for moisture damage. Results found that use of WMA impacts both construction and performance properties. To account for these factors an evaluation framework to select appropriate production temperatures for WMA was introduced that is based on evaluation of mixture volumetrics, compactability, resistance to moisture damage, and rutting performance. Furthermore, to facilitate the mixture design and temperature selection process surrogate test methods to evaluate workability and performance properties of the asphalt binder as well as the integrity of the bond at the asphalt/binder aggregate interface were proposed and verified through relationships with mixture performance.
