Performance Evaluation Of Recycled Asphalt Shingles Ras In Hot Mix Asphalt Hma
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Performance Evaluation Of Recycled Asphalt Shingles Ras In Hot Mix Asphalt Hma
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Author : Riyad-UL. Islam
language : en
Publisher:
Release Date : 2011
Performance Evaluation Of Recycled Asphalt Shingles Ras In Hot Mix Asphalt Hma written by Riyad-UL. Islam 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.
Today, a large quantity of waste is generated from the replacement of residential and commercial roofs. Many of the roofs being upgraded with previously constructed from asphalt shingles. Recycled Asphalt Shingles (RAS) contain nearly 30% of asphalt cement by mass, which can be a useful additive to asphalt pavements. In addition, shingles can offer significant potential savings through recycling and recovery as a construction material in flexible pavement. Currently, one and a half million tons of roofing shingle waste is generated each year in Canada related to the replacement of residential and commercial roofs and 90% of this valuable material is sent to landfills. If engineered properly, the addition of RAS into Hot Mix Asphalt (HMA) can provide significant benefits. The University of Waterloo's Centre for Pavement and Transportation Technology (CPATT) is committed to working with public and private sector partners to develop sustainable technologies for the pavement industry. Using RAS in HMA can lead to economical, environmental and social benefits. Examples of which are reduced waste going to landfills and a reduction in the quantity of virgin material required. This research has involved the Ontario Centres of Excellence (OCE) and Miller Paving Limited. It was conducted to evaluate the performance of HMA containing RAS in both field and laboratory tests.
Initial Performance Assessment For Implementation Of Hot Mix Asphalt Containing Recycled Asphalt Shingles In Oregon
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Author : Faisal Ahmed Samoo
language : en
Publisher:
Release Date : 2011
Initial Performance Assessment For Implementation Of Hot Mix Asphalt Containing Recycled Asphalt Shingles In Oregon written by Faisal Ahmed Samoo 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.
This thesis documents the evaluation of the initial performance of pavement containing recycled asphalt shingles (RAS) in Oregon. The research was funded by the Oregon Department of Transportation (ODOT) and the Federal Highway Administration and was conducted at Oregon State University. The key objectives of this thesis are to document the state-of-the-practice for implementation of recycled asphalt shingles in hot mix asphalt (HMA) mixtures, and to evaluate the initial field and laboratory performance of mixtures containing RAS. Recent oil price increases, coupled with environmental impacts has encouraged industry to use materials containing asphalt binder, such as asphalt shingles as a partial replacement of virgin materials in the construction of bituminous pavement. Residential home reroofing projects generate RAS as does the asphalt shingle manufacturing industry as a waste product at a rate of approximately 11 million tons per year nationwide. Disposal of these materials ordinarily involves discarding the materials in landfills. However, since these shingles contain asphalt binder, many states and asphalt pavement contractors have made efforts to incorporate these materials into asphalt pavements. Asphalt shingles are produced with asphalt binders that have substantially higher stiffness than paving grade asphalt binders. With increased stiffness comes increased brittleness. Consequently, incorporating RAS into hot mix asphalt may expose the pavement to an increased likelihood of low temperature cracking and fatigue cracking unless modifications are made to the mixtures to compensate for increased stiffness due to the RAS binder. House Bill 2733, proposed before the Oregon Legislative Assembly in 2009, would have required ODOT to use up to 5% RAS in HMA. However, inclusion of RAS in HMA raised concerns within the agency with regard to the potential for reduction in pavement performance ultimately leading to increased costs due to early failures. Consequently, considering these concerns the legislation on this bill was postponed pending completion of research to investigate the performance of pavement containing RAS in Oregon pavements. As a result, ODOT sponsored preliminary research on use of RAS in HMA in 2009 and subsequently through the research project described herein. The research work described herein was separated into three distinct but interconnected tasks. The first involved conducting a detailed literature review to gain an understanding of the state-of-the-practice for successful implementation of RAS in pavements. Emphasis during this effort was placed on selection of the virgin binder grade to offset the effects of increased stiffness due to incorporation of RAS binder, batching and mixing procedures for inclusion of RAS in HMA mixtures, ignition oven calibration factors for mixtures containing RAS, and quality control/quality assurance procedures for pavements built with RAS mixtures. There exists a substantial body of literature covering use of recycled asphalt pavement (RAP) as a partial replacement of virgin materials in HMA pavements. Due to many similarities of RAP and RAS, many of the documents reviewed covered only RAP, but with the aim of extending the technologies used for RAP mixtures to those containing RAS or RAS and RAP. The second task involved conducting laboratory investigations to verify the practicality and effectiveness of procedures found in the literature for batching and mixing materials containing RAS and/or RAP and RAS. Finally, the third task involved investigations of performance of two pavements containing RAP and RAS constructed as pilot projects. The investigations involved an assessment of field performance and laboratory tests on samples obtained from the two pavements. For comparison purposes, the same investigations were performed on pavements and samples from pavements that contained RAP but no RAS. These were constructed adjacent to, and at the same time as, the pavements with RAP and RAS. Based on the findings from the literature review, this thesis contains recommendations for: 1) selection of a virgin binder grade when RAP and/or RAS is used in an HMA mixture; 2) a procedure for effectively and efficiently extracting and recovering asphalt binder from RAS; 3) batching and mixing procedures for manufacturing laboratory test specimens containing RAS; 4) a method for determining ignition over calibration factors for mixtures containing RAS; and 5) quality control/quality assurance procedures for pavements built with RAS mixtures. The recommended batching and mixing procedure was verified through laboratory investigations while ongoing research is in the process of verifying the remaining procedures. Laboratory investigations involving dynamic modulus testing and comparative analyses of RAP-only mixtures (control mixtures) versus RAP and RAS mixtures indicated a trend of reduced dynamic modulus due to the addition of RAS in the mixture on both pilot projects. However, when the mixtures were compared at a 95 percent confidence level, a significant difference was found for only one of the two projects. This reduction in dynamic modulus was likely due to the softening of blended binder and the increased air voids in the mixtures containing RAS. In addition, fatigue testing and comparative analyses using phenomenological and dissipated energy approaches indicated that there was no significant difference in fatigue resistance of the RAP-only mixture versus the RAP and RAS mixture at a 95 percent confidence level. Assessment of field performance through visual inspections of the pavements built with mixtures containing RAS revealed no low temperature cracking following the first winter season in service. Nor did the inspections reveal any fatigue cracking. Although these inspections occurred within 8 months of construction of the pavements, the findings provide encouraging early-life performance of the mixtures.
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."--
Performance Of Recycled Asphalt Shingles In Hot Mix Asphalt
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Author :
language : en
Publisher:
Release Date : 2013
Performance Of Recycled Asphalt Shingles In Hot Mix Asphalt written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Asphalt categories.
State highway agencies are increasingly intersted in using recycled asphalt shingles (RAS) in hot mix asphalt (HMA) applications, yet many agencies share common questions about the effect of RAS on the performance of HMA. Previous research has allowed for only limited laboratory testing and field surveys. The complexity of RAS materials and lack of past experiences led to the creation of Transportation Pooled Fund (TPF) Program TPF-5(213). The primary goal of this study is to address research needs of state DOT and environmental officials to determine the best practices for the use of recycled asphalt shingles in hot-mix asphalt applications. Agencies participating in the study include Missouri (lead state), California, Colorado, Illinois, Indiana, Iowa, Minnesota, Wisconsin, and the Federal Highway Administration. The agencies conducted demonstration projects that focused on evaluating different aspects (factors) of RAS that include RAS grind size, RAS percentage, RAS source (post-consumer versus post-manufactured), RAS in combination with warm mix asphalt technology, RAS as a fiber replacement for stone matrix asphalt, and RAS in combination with ground tire rubber. Field mixes from each demonstration project were sampled for conducting the following tests: dynamic modulus, flow number, four-point beam fatigue, semi-circular bending, and binder extraction and recovery with subsequent binder characterization. Pavement condition surveys were then conducted for each project after completion. The demonstration projects showed that pavements using RAS alone or in combination with other cost saving technologies (e.g., WMA, RAP, GTR, SMA) can be successfully produced and meet state agency quality assurance requirements. The RAS mixes have very promising prospects since laboratory test results indicate good rutting and fatigue cracking resistance with low temperature cracking resistance similar to the mixes without RAS. The pavement condition of the mixes in the field aft
Performance Of Recycled Asphalt Shingles In Hot Mix Asphalt
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Author : R. Christopher Williams
language : en
Publisher:
Release Date : 2013
Performance Of Recycled Asphalt Shingles In Hot Mix Asphalt written by R. Christopher Williams and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Asphalt concrete categories.
State highway agencies are increasingly intersted in using recycled asphalt shingles (RAS) in hot mix asphalt (HMA) applications, yet many agencies share common questions about the effect of RAS on the performance of HMA. Previous research has allowed for only limited laboratory testing and field surveys. The complexity of RAS materials and lack of past experiences led to the creation of Transportation Pooled Fund (TPF) Program TPF-5(213). The primary goal of this study is to address research needs of state DOT and environmental officials to determine the best practices for the use of recycled asphalt shingles in hot-mix asphalt applications. Agencies participating in the study include Missouri (lead state), California, Colorado, Illinois, Indiana, Iowa, Minnesota, Wisconsin, and the Federal Highway Administration. The agencies conducted demonstration projects that focused on evaluating different aspects (factors) of RAS that include RAS grind size, RAS percentage, RAS source (post-consumer versus post-manufactured), RAS in combination with warm mix asphalt technology, RAS as a fiber replacement for stone matrix asphalt, and RAS in combination with ground tire rubber. Field mixes from each demonstration project were sampled for conducting the following tests: dynamic modulus, flow number, four-point beam fatigue, semi-circular bending, and binder extraction and recovery with subsequent binder characterization. Pavement condition surveys were then conducted for each project after completion. The demonstration projects showed that pavements using RAS alone or in combination with other cost saving technologies (e.g., WMA, RAP, GTR, SMA) can be successfully produced and meet state agency quality assurance requirements. The RAS mixes have very promising prospects since laboratory test results indicate good rutting and fatigue cracking resistance with low temperature cracking resistance similar to the mixes without RAS. The pavement condition of the mixes in the field after two years corroborated the laboratory test results. No signs of rutting, wheel path fatigue cracking, or thermal cracking were exhibited in the pavements. However, transverse reflective cracking from the underlying jointed concrete pavement was measured in the Missouri, Colorado, Iowa, Indiana, and Minnesota projects.
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.
New Generation Mix Designs
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Author : Lubinda F. Walubita
language : en
Publisher:
Release Date : 2013
New Generation Mix Designs written by Lubinda F. Walubita and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Accelerated life testing categories.
Recent changes to the Texas hot mix asphalt (HMA) mix-design procedures such as adaption of the higher-stiffer performance grade asphalt-binder grades and the Hamburg test have ensured that the mixes that are routinely used on the Texas highways are not prone to rutting. However, performance concerns have been raised with these HMA mixes that are now drier, more difficult to compact, and more susceptible to premature cracking. This is particularly problematic with the dense-graded mixes (Type C and D) that are widely used throughout the state of Texas. Therefore, there has been a great need to either: (1) modify the existing Texas HMA mix-design criteria and/or to include new simpler cracking test procedures; or (2) develop new mix-design methods that will optimize HMA field performance, particularly with respect to cracking. As a means toward addressing these issues, this report provides documentation of a 4-year research study that included the following major tasks: a) comparative evaluation of the Texas gyratory and balanced mix design (BMD) methods; b) development and evaluation of numerous HMA mix designs including reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) mixes, c) extensive laboratory test including Hamburg rutting and Overlay Tester crack evaluations; d) accelerated pavement testing and performance evaluation; e) field testing and performance monitoring of in-service highway test sections. Based on the study findings and as documented herein, recommendations for updates and modifications to the Texas HMA mix-design methods were made. Additionally, new guidelines and specifications were also developed for new generation HMA mix-design procedures. Overall, the BMD method that is rutting-cracking performance based exhibited superiority over the traditional Texas gyratory mix-design method, particularly in terms of HMA mix constructability and cracking performance.
Evaluation Of The Effect Of Recycled Asphalt Shingles On Ontario Hot Mix Pavement
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Author : Shirley Jacqueline Ddamba
language : en
Publisher:
Release Date : 2011
Evaluation Of The Effect Of Recycled Asphalt Shingles On Ontario Hot Mix Pavement written by Shirley Jacqueline Ddamba 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.
Due to the 15-20 year life span of roofing shingles, 1.5 million tonnes of asphalt roofing shingles are being demolished and replaced annually in Canada from both residential and commercial facilities. These roofing shingles are manufactured from very high quality materials which are considered a valuable by-product. Recycled Asphalt Shingles (RAS), a product containing approximately 30% asphalt cement by mass, is a valuable additive to Hot Mix Asphalt (HMA) pavements and a potential savings for the construction industry. Recycling of demolished asphalt shingles is a significant new step forward in abating the need to put the waste into landfills. This re-use creates a great opportunity in reducing materials being dumped at landfills while providing an additive to HMA mixtures for paving. Therefore, this leads to economic, environmental, and social benefits for all the stakeholders and road users such as reduced need for landfill space, conservation of virgin materials and environment, and financial saving.
Incorporation Of Recycled Asphalt Shingles In Hot Mixed Asphalt Pavement Mixtures
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Author : Jim McGraw
language : en
Publisher:
Release Date : 2010
Incorporation Of Recycled Asphalt Shingles In Hot Mixed Asphalt Pavement Mixtures written by Jim McGraw and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Pavements, Asphalt categories.
Rises in construction and asphalt binder costs, as well as the growing pressures on landfills, have contributed to the increased use of tear-off scrap shingles (TOSS) and manufacturer waste scrap shingles (MWSS) into hot-mixed asphalt (HMA) pavement mixtures. This research project was undertaken to address the responsible incorporation of recycled asphalt shingles (RAS) into HMA pavement mixtures to ensure environmental benefits are realized and pavement durability is retained or improved. The research consisted of a literature review, extensive laboratory testing and field evaluations of in service RAS/RAP HMA pavements. Binder testing established a strong correlation between the new asphalt binder to total asphalt binder ratio and the extracted high/low binder performance grade temperatures. Dynamic modulus testing on HMA mixtures proved to be an invaluable tool in comparing the effects of RAS and RAP on mixture properties across a wide range of temperatures. Field performance appeared to validate the laboratory findings in some instances.
Comprehensive Performance Evaluation Of In Place Recycled Hot Mix Asphalt As Unbound Granular Material
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Author :
language : en
Publisher:
Release Date : 2009
Comprehensive Performance Evaluation Of In Place Recycled Hot Mix Asphalt As Unbound Granular Material written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with categories.
A promising pavement rehabilitation strategy that is of interest to state highway agencies and local governments involves the in-place pulverization of failed hot mix asphalt (HMA) pavements and re-use of the pulverized material as a granular base material. Advantages of this technique include a reduction in the use of virgin aggregate, a reduction in the amount of construction traffic, and removal of the potential for reflective cracking from the existing cracked pavement layers through the new HMA surface. However, the performance of this technique has not been comprehensively evaluated, and, in particular, permanent deformation characteristics. In this thesis, four pilot projects in northeastern California were used to evaluate the pulverized material and this rehabilitation strategy. The characteristics and performance of the pulverized material were evaluated by comprehensive laboratory and field testing, and analyses. Based on the multistage repeated load triaxial test results, the shakedown limits of the pulverized material were estimated and compared with the stress states calculated from the cross-anisotropic finite element analyses based on real traffic and climate data. A recursive-incremental damage model was used to predict permanent deformation of the pulverized base layer over the long term and to compare it with that of typical aggregate base material. Based on the comprehensive laboratory testing, field testing, and analyses, the pulverized material was found to be generally stiffer than typical aggregate base material, possibly due to better aggregate shape than that found in typical aggregate base material. The pulverized mateiral has less permanent deformation resistance at low stress levels but greater resistance at higher stress levels than typical granular material used in California. Possible reasons for the lower permanent deformation resistance at low stress levels might be the laboratory compaction method and that the recycled HMA in the pulverized material undergoes additional breakdown under initial loading since coarse fractions of the pulverized materials are greater than that of the comparison virgin aggregate base. Overall, the performance benefits of this rehabilitation strategy make it a viable option for flexible pavement rehabilitation.