Characterisation of Warm Asphalt Mixtures with Addition of Reclaimed Asphalt Pavement Materials PDF Download
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Author: D. M. Abd
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: D. M. Abd
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Beaux M. Kemp
Publisher:
ISBN:
Category : Pavements, Asphalt
Languages : en
Pages : 308
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Recycled asphalt pavement (RAP) material has been combined with hot-mix asphalt (HMA) paving for several decades to reduce construction costs and environmental impacts. In Alaska, the HMA specification allows up to 15% RAP for Type-II A mixes (typically used in wearing courses) and 25% for Type II-B mixes (used in wearing or base courses). Highway construction projects statewide are expected to see an increase in the use of RAP in future mix designs. Pavement engineers use mechanistic procedures (e.g. Alaska Flexible Pavement Design software and Mechanistic-Empirical Pavement Design Guide) to develop flexible pavement design alternatives. These procedures require material engineering properties as an input source. Consequently, it is essential to properly establish the engineering properties of HMA mixtures containing RAP. In order to characterize Alaskan HMA materials containing RAP, this study evaluated 11 HMA mixtures comprised of three typical Alaskan asphalt binders (PG 52-28, PG 58-34 and PG 52-40) containing 0%, 25% and 35% RAP that were either produced in the lab or a hot-plant (i.e. collected from actual paving projects in Alaska). Various binder and mix properties were determined including; true high binder grades, complex shear modulus (G*) and phase angle (delta) at high performance temperatures, as well as asphalt mixture performance tests (AMPT); dynamic modulus (E*) and flow number (FN). The original (h-based) and the modified (G*-based) Witczak (E*) predictive models were evaluated for these mixtures based on job mix formulae availability for use in mechanistic design procedures. It was found that the incorporation of RAP into Alaskan HMA increased E* and FN of the mixtures, which indicates that the addition of RAP increased the stiffness and rutting resistance of the mixtures tested. A local calibration of the Witczak predictive models may be required for increased accuracy of E* predictions. For Alaskan conditions, a savings of $13.60/ton of mix was estimated for a 25% RAP mix. For an 18-feet wide one lane-mile of HMA mat, it is estimated to have a 21% savings in the 25% RAP mix compared to the conventional virgin (no RAP) mix.
Author:
Publisher: Transportation Research Board
ISBN: 0309155649
Category : Asphalt concrete
Languages : en
Pages : 285
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 192
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Author: Brian Hill
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Category :
Languages : en
Pages :
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Sustainability is a cornerstone of today0́9s engineering world. Warm mix asphalt (WMA) and reclaimed asphalt pavement (RAP) are the most prominent sustainable materials in asphalt concrete pavements. WMA is a not a new concept, however new innovations and increased usage of WMA has been spurred by the increased focus on sustainable infrastructure systems. WMA enables reduced production temperatures through the use of wax, water, or other chemical packages. The effects of reduced production temperatures include fuel use and emissions reductions, improved compaction, and possible RAP concentration increases. RAP is the primary recycled product of the aged asphalt concrete pavements and its use leads to reductions in virgin aggregate and asphalt demand. However, significant performance issues can stem from the individual integration of WMA or RAP materials in asphalt concrete. In particular, WMA technologies can increase moisture and rutting susceptibility while RAP significantly increases the stiffness of the resulting mixture. Consequently, quality performance of sustainable asphalt pavements may require the combined use of WMA and RAP to produce mixtures with sufficient stiffness and moisture and fracture resistance. This study evaluates the potential of WMA technologies and their integration with RAP. Initially, an extensive literature review was completed to understand the advantages, disadvantages, and past field and lab performance of WMA and RAP mixtures. Rotational viscometer and bending beam rheometer tests were then used to evaluate Sasobit, Evotherm M1, and Advera WMA modified and unmodified binders. Finally, virgin and 45% RAP mixtures were designed and tested to examine the rutting, moisture, and fracture resistance of WMA and HMA mixtures. The results of this experiment provided several key observations. First, viscosity reductions may not be the primary cause for the availability of reduced production temperatures for WMA technologies. Second, WMA additive properties have a significant effect upon fracture, moisture, and rutting resistance. Furthermore, the addition of RAP to WMA mixtures improved the rutting and moisture sensitivity performance as characterized in the Hamburg and Tensile Strength Ratio testing procedures.
Author: Asphalt Institute
Publisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 160
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Author: Francesco Canestrari
Publisher: Springer
ISBN: 9401773424
Category : Technology & Engineering
Languages : en
Pages : 1024
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This work presents the results of RILEM TC 237-SIB (Testing and characterization of sustainable innovative bituminous materials and systems). The papers have been selected for publication after a rigorous peer review process and will be an invaluable source to outline and clarify the main directions of present and future research and standardization for bituminous materials and pavements. The following topics are covered: - Characterization of binder-aggregate interaction - Innovative testing of bituminous binders, additives and modifiers - Durability and aging of asphalt pavements - Mixture design and compaction analysis - Environmentally sustainable materials and technologies - Advances in laboratory characterization of bituminous materials - Modeling of road materials and pavement performance prediction - Field measurement and in-situ characterization - Innovative materials for reinforcement and interlayer systems - Cracking and damage characterization of asphalt pavements - Recycling and re-use in road pavements This is the proceedings of the RILEM SIB2015 Symposium (Ancona, Italy, October 7-9, 2015).
Author:
Publisher:
ISBN:
Category : Asphalt
Languages : en
Pages : 720
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Author: Ramon Francis Bonaquist
Publisher: Transportation Research Board
ISBN: 0309087821
Category : Medical
Languages : en
Pages : 169
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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.
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Category : Pavements, Asphalt concrete
Languages : en
Pages : 45
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The proposed Mechanistic-Empirical Pavement Design Guide (MEPDG) procedure is an improved methodology for pavement design and evaluation of paving materials. Since this new procedure depends heavily on the characterization of the fundamental engineering properties of paving materials, a thorough material characterization of mixes used in Virginia is needed to use the MEPDG to design new and rehabilitated flexible pavements. The primary objective of this project was to perform a full hot-mix asphalt (HMA) characterization in accordance with the procedure established by the proposed MEPDG to support its implementation in Virginia. This objective was achieved by testing a sample of surface, intermediate, and base mixes. The project examined the dynamic modulus, the main HMA material property required by the MEPDG, as well as creep compliance and tensile strength, which are needed to predict thermal cracking. In addition, resilient modulus tests, which are not required by the MEPDG, were also performed on the different mixes to investigate possible correlations between this test and the dynamic modulus. Loose samples for 11 mixes (4 base, 4 intermediate, and 3 surface mixes) were collected from different plants across Virginia. Representative samples underwent testing for maximum theoretical specific gravity, asphalt content using the ignition oven method, and gradation of the reclaimed aggregate. Specimens for the various tests were then prepared using the Superpave gyratory compactor with a target voids in total mix (VTM) of 7% ± 1% (after coring and/or cutting). The investigation confirmed that the dynamic modulus test is an effective test for determining the mechanical behavior of HMA at different temperatures and loading frequencies. The test results showed that the dynamic modulus is sensitive to the mix constituents (aggregate type, asphalt content, percentage of recycled asphalt pavement, etc.) and that even mixes of the same type (SM-9.5A, IM-19.0A, and BM 25.0) had different measured dynamic modulus values because they had different constituents. The level 2 dynamic modulus prediction equation reasonably estimated the measured dynamic modulus; however, it did not capture some of the differences between the mixes captured by the measured data. Unfortunately, the indirect tension strength and creep tests needed for the low-temperature cracking model did not produce very repeatable results; this could be due to the type of extensometers used for the test. Based on the results of the investigation, it is recommended that the Virginia Department of Transportation use level 1 input data to characterize the dynamic modulus of the HMA for projects of significant impact. The dynamic modulus test is easy to perform and gives a full characterization of the asphalt mixture. Level 2 data (based on the default prediction equation) could be used for smaller projects pending further investigation of the revised prediction equation incorporated in the new MEPDG software/guide. In addition, a sensitivity analysis is recommended to quantify the effect of changing the dynamic modulus on the asphalt pavement design. Since low-temperature cracking is not a widespread problem in Virginia, use of level 2 or 3 indirect tensile creep and strength data is recommended at this stage.
