Effect Of Warm Mix Asphalt On Recycled Asphalt Pavement In Hot Mix Asphalt
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Effect Of Warm Mix Asphalt On Recycled Asphalt Pavement In Hot Mix Asphalt
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Author : Thomas Bennert
language : en
Publisher:
Release Date : 2015
Effect Of Warm Mix Asphalt On Recycled Asphalt Pavement In Hot Mix Asphalt written by Thomas Bennert and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with Asphalt emulsion mixtures categories.
Blending Issues Of Hot And Warm Mix Asphalt Containing Recycled Asphalt Pavement And Recycled Asphalt Shingle
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Author : Sheng Zhao (Writer on pavements)
language : en
Publisher:
Release Date : 2014
Blending Issues Of Hot And Warm Mix Asphalt Containing Recycled Asphalt Pavement And Recycled Asphalt Shingle written by Sheng Zhao (Writer on pavements) and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with Asphalt categories.
The current tendency in paving industry is to increase the use of recycled asphalt pavement (RAP) and recycled asphalt shingle (RAS). However, one of the reasons that limit the high recycled amount is the unknown blending between virgin and RAP/RAS binders. A series of studies were conducted in this dissertation to address blending issues in warm mix asphalt (WMA) and hot mix asphalt (HMA) containing RAP and RAS, in terms of evaluation of recycled binder mobilization, binder homogeneity and WMA effects on blending. Partial blending was observed in RAS mixtures and the most efficient blending occurred at approximately 5% RAS by weight. Increasing time led to a better RAS binder mobilization, while aggregate size and temperature in a certain range showed limited effects. A new parameter derived from gel permeation chromatography (GPC), large molecular size percentage [LMS(%)] related to binder molecular weight distribution, was developed to differentiate virgin and RAP/RAS binders as well as their blends, based on which a method was developed to quantify the recycled binder mobilization rate. A two-layer model based on atomic force microscopy (AFM) scanning was developed to evaluate RAS and virgin binder blending. The two binders were found to be “mixing” but not “blending” in a mixing zone of 25 to 30 micrometer. Staged extraction method used to evaluate asphalt binder homogeneity was validated with trichloroethylene (TCE) as the most effective solvent. A non-equal-time staged extraction method was proposed, in conjunction with LMS(%), to quantify binder homogenization after mechanical mixing and diffusion. Different blending scenarios of RAP/RAS mixes were proposed and validated. It was found that diffusion could be accomplished within mixture storage time for both WMA and HMA containing RAP, while blending in RAS mix was limited. WMA additives yielded mixes with higher blending ratios than control mix produced at 135oC, but lower than hot mix produced at 165oC. Laboratory foaming yielded a higher blending ratio, indicating foamed WMA may improve blending. Rutting might still be a concern for WMA-high RAP mixtures while fatigue concern may not exist. WMA-high RAP mixtures showed satisfactory moisture resistance. Blending effects on performance still needs further investigation.
Evaluating The Effects Of Recycling Agents On Asphalt Mixtures With High Ras And Rap Binder Ratios
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Author : Amy Epps Martin
language : en
Publisher:
Release Date : 2020
Evaluating The Effects Of Recycling Agents On Asphalt Mixtures With High Ras And Rap Binder Ratios written by Amy Epps Martin and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with Asphalt categories.
"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."--
A Manual For Design Of Hot Mix Asphalt With Commentary
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Author :
language : en
Publisher: Transportation Research Board
Release Date : 2011
A Manual For Design Of Hot Mix Asphalt With Commentary written by and has been published by Transportation Research Board this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with Asphalt concrete categories.
Effect Of Recycled Asphalt Pavement On Mechanistic Performance Of Hot Mix Asphalt
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Author : Adjamoussi David Adje
language : en
Publisher:
Release Date : 2012
Effect Of Recycled Asphalt Pavement On Mechanistic Performance Of Hot Mix Asphalt written by Adjamoussi David Adje and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with Pavements, Asphalt categories.
Laboratory Evaluation Of Warm Mix Asphalt Influence On Theoretical Maximum Specific Gravity
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Author : Jianhua Yu
language : en
Publisher:
Release Date : 2012
Laboratory Evaluation Of Warm Mix Asphalt Influence On Theoretical Maximum Specific Gravity written by Jianhua Yu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with Asphalt concrete categories.
Warm mix asphalt (WMA) technology provides sufficient workability for asphalt mixtures at reduced mixing and compaction temperatures. Depending on the WMA technology, the typical temperature reduction range is 20 °C to 55 °C below hot mix asphalt (HMA) production temperatures. WMA involves chemical and wax additives that are added to an asphalt binder or incorporated through the use of foaming technology. The main advantages of WMA are reduced emissions and a reduction in combustible fuel consumption. Ongoing WMA research projects have documented some differences between HMA and WMA mixes, prompting numerous research projects that are investigating these concerns. The purpose of this research is to evaluate the volumetric properties by directly comparing laboratory produced WMA and HMA mixes. This study investigates the impact of WMA additives on the volumetric properties, specifically, the theoretical maximum specific gravity (Gmm). The Gmm testing followed the procedure of ASTM D2041. Two mix designs with HMA binder were produced, one without recycled asphalt pavement (RAP) and the other with 30 % RAP. After the mix designs were completed, no additional changes were made to account for the addition of the WMA technology. The mixes included the WMA technologies Sasobit and Advera, as well as an HMA control, for a total of six different laboratory produced mixes. Each mix was produced at 120 °C, 135 °C, and 150 °C, and each mix was oven cured for 1, 2, and 4 h. The test results were analyzed using statistical principles to determine whether differences in the Gmm values were statistically significant. The results show that temperature has little impact on Gmm. Gmm was not affected by curing times of 1 and 2 h, but the longer curing time of 4 h resulted in a statistically significant increase in Gmm. Further analysis revealed that the mix sensitivity to curing time depends on the amount of RAP in the mix. For the mix designs studied, the Advera Gmm values were similar to the HMA values, but the Sasobit Gmm values were statistically lower than the Advera values.
Effect Of Reclaimed Asphalt Pavement On Ontario Hot Mix Asphalt Performance
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Author : Xiomara A. Sanchez-Castillo
language : en
Publisher:
Release Date : 2014
Effect Of Reclaimed Asphalt Pavement On Ontario Hot Mix Asphalt Performance written by Xiomara A. Sanchez-Castillo and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with categories.
The use of Reclaimed Asphalt Pavement (RAP), sometimes called Recycled Asphalt Pavement, in Hot Mix Asphalt (HMA) provides many benefits and has been successfully used in Ontario for several years. The production and usage of this material results in numerous environmental and economic advantages. Using RAP in HMA has various proven benefits including: reuse of high quality materials, saves on dwindling non-renewable aggregate resources, diverts large volumes of materials from overloaded landfills, reduces road building costs and contributes significantly to provincial and municipal recycling obligations. However, the usage of this material is still very conservative. Several challenges can be faced when introducing RAP in HMA, particularly in higher amounts. The characteristics of the RAP, particularly the aged (stiffer) asphalt cement (AC) in the recycled material, can affect the performance of the mix. The primary concern with increasing RAP percentages in HMA mixes are its effects on endurance against fatigue and thermal cracking. The common question in many agencies within the pavement industry is whether RAP acts as a “black rock” or the aged AC in RAP blends with the new AC in the mix. Accordingly, this research evaluated the impact that RAP in varying percentages has on a conventional Ontario mix, Superpave (SP) 12.5mm, and provided some new guidelines on the usage of RAP. Using virgin aggregates and RAP collected from a local contractor, twelve mixtures were modelled in the laboratory, with 0%, 20%, and 40% RAP contents and AC with different Performance Grade (PG). The research also examined how the addition of RAP to HMA alters the performance of the mix, and how HMA can be tested to determine the RAP content. This research intended to answer the following questions: First, can the RAP percentage be determined from the recycled hot mix asphalt characteristics or performance? And second, can the blended binder PG be deduced from performance testing of recycled hot mix? This research demonstrated that is possible to design Superpave mixes incorporating 20% RAP and 40% RAP without compromising the specified consensus properties and volumetric characteristics. Based on the results, it was determined that the performance of the recycled hot mixes regarding low temperature cracking, rutting and stiffness, which is related to the fatigue susceptibility of the mix, was simultaneously influenced by the RAP content and the virgin asphalt PG. The effect of the RAP addition was more dramatic for the mixes with virgin binder PG 52-xx than for the mixes with PG 58-xx. A method to determine the presence and quantity of RAP was formulated, and also an estimation of the performance grade of the resulting blended binder without extraction and recovery of the asphalt was possible.
Performance Evaluation Of Warm Mix Asphalt Mixtures Incorporating Reclaimed Asphalt Pavement
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Author : Brian Hill
language : en
Publisher:
Release Date : 2011
Performance Evaluation Of Warm Mix Asphalt Mixtures Incorporating Reclaimed Asphalt Pavement written by Brian Hill and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
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.
Evaluation Of Moisture Damage In Warm Mix Asphalt Containing Recycled Asphalt Pavement
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Author : Emily Dawn Shrum
language : en
Publisher:
Release Date : 2010
Evaluation Of Moisture Damage In Warm Mix Asphalt Containing Recycled Asphalt Pavement written by Emily Dawn Shrum and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
Warm mix asphalt (WMA) has been used worldwide for many years, primarily in Europe. The National Asphalt Pavement Association first brought WMA to the United States in 2002. By using warm mix technology, the temperature of an asphalt mixture during production, transportation, and compaction decreases dramatically. Several concerns about WMA arise due to the reduced mixing temperature. One of the primary concerns in asphalt pavement is the moisture damage. The lower mixing temperature may not be high enough to vaporize all the moisture absorbed in the aggregate, and part of the moisture may be entrapped in the pavements during compaction. This thesis presents a laboratory study to evaluate the moisture susceptibility of warm mix asphalt (WMA) produced through plant foaming procedure. Two types of mixtures were evaluated. A base mixture meeting the state of Tennessee "BM-2" mix criteria was evaluated at 0, 30, 40, and 50 percent fractionated recycled asphalt pavement (RAP), and a surface mixture meeting the state of Tennessee "411-D" mix criteria was evaluated at 15, 20, 30, 40 percent fractionated RAP. WMA mixture specimens were obtained and compacted at the asphalt plant. The WMA specimens were compared to hot-mix asphalt (HMA) specimens through a set of laboratory mixture performance tests. In addition to traditional AASHTO T283 freeze and thaw (F-T) tensile strength ratio (TSR), Superpave indirect tensile test (IDT) with F-T and MIST conditioning, and Asphalt Pavement Analyzer (APA) Hamburg wheel tracking tests were utilized to evaluate asphalt mixtures. Moisture tests indicated that with the higher inclusions of RAP, specimens exhibited lower rut depths and higher tensile strength retention. Tensile strength ratio tests indicated that HMA specimens had higher tensile strength retention when freeze thaw conditioned. Dynamic modulus conditioned specimens indicated that simple performance tests can show the difference between conditioned and unconditioned specimens. HMA specimens showed lower susceptibility to moisture compared to WMA specimens for both BM-2 and 411-D mixtures. The higher percentages of RAP in WMA and HMA in both BM-2 and 411-D mixtures showed a reduction to moisture susceptibility.
Improved Mix Design Evaluation And Materials Management Practices For Hot Mix Asphalt With High Reclaimed Asphalt Pavement Content
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Author : Randy Clark West
language : en
Publisher: Transportation Research Board
Release Date : 2013
Improved Mix Design Evaluation And Materials Management Practices For Hot Mix Asphalt With High Reclaimed Asphalt Pavement Content written by Randy Clark West and has been published by Transportation Research Board this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Pavements, Asphalt categories.
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.