Evaluation Of Reclaimed Asphalt Pavement For Surface Mixtures
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Evaluation Of Reclaimed Asphalt Pavement For Surface Mixtures
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Author : Rebecca McDaniel
language : en
Publisher: Purdue University Press
Release Date : 2012-08-01
Evaluation Of Reclaimed Asphalt Pavement For Surface Mixtures written by Rebecca McDaniel and has been published by Purdue University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-08-01 with categories.
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.
Characterization Of Reclaimed Asphalt And Performance Based Evaluation Of Its Use In Recycled Mixtures
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Author : Jesse David Doyle
language : en
Publisher:
Release Date : 2011
Characterization Of Reclaimed Asphalt And Performance Based Evaluation Of Its Use In Recycled Mixtures written by Jesse David Doyle and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with Asphalt categories.
Reclaimed asphalt pavement (RAP) is a valuable resource that can be recycled into new asphalt mixtures. In recent years, the continued rise of raw material costs has generated considerable interest in increasing RAP usage. Warm mix asphalt (WMA) is a modern development in the asphalt industry that can potentially help increase RAP usage and achieve adequate mixture performance. The purpose of this dissertation is to: 1) develop a method to characterize the absorbed, inert and effective bituminous components in RAP; and 2) evaluate performance of high RAP-WMA mixtures for various pavement applications including airfield surfaces, highway surfaces and highway bases. A unique approach was taken to characterize RAP properties that coupled a dataset of 568 asphalt mix designs spanning five years of practice and testing 100% RAP with added virgin binder; 394 compacted specimens and 68 loose specimens were tested. A method to predict RAP absorbed asphalt was developed and shown to yield more reasonable results than conventional methods which were shown very likely to give incorrect absorbed asphalt contents in some conditions. The relative effectiveness of RAP surface asphalt was evaluated and estimates of inert and effective RAP asphalt were made for a variety of temperature, compactive effort, and warm mix additive conditions. Results showed different behaviors between RAP sources and between hot and warm mix temperatures. These results were also observed in volumetrics of high RAP mixtures. Performance evaluation was based on testing 75 slab specimens and more than 1100 gyratory specimens. Test data indicated a potential for decreased durability as RAP content increases; however 25% RAP highway surface mixtures and 50% RAP base mixtures had similar performance to current practice. Low temperature mixture stiffness testing and thermal cracking analysis indicated slightly increased stiffness with high RAP and 25% RAP highway surface mixtures that had comparable performance to current practice. Dry rut testing indicated high RAP mixtures are rut resistant. Moisture damage testing of high RAP mixtures indicated passing results in tensile strength ratio testing but potential for moisture damage in loaded wheel tracking. Overall, 25% RAP highway surface mixtures are recommended for immediate implementation.
Evaluation Of Reclaimed Asphalt Pavement Materials From Ultra Thin Bonded Bituminous Surface
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Author : Haritha Yadav Musty
language : en
Publisher:
Release Date : 2012
Evaluation Of Reclaimed Asphalt Pavement Materials From Ultra Thin Bonded Bituminous Surface written by Haritha Yadav Musty and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
The ultra-thin bonded bituminous surface (UBBS), popularly known as Novachip, is a thin hot-mix asphalt layer with high-quality, gap-graded aggregates bonded to the existing surface with a polymer-modified emulsion membrane. This thin surfacing improves ride quality, reduces road-tire noise, minimizes back spray, and increases visibility under wet conditions. The Kansas Department of Transportation (KDOT) has been using UBBS since 2002. Performance of this thin surface treatment strategy has been good in Kansas and elsewhere. However, some of these projects are now being rehabilitated. The objective of this study is to evaluate whether reclaimed asphalt pavement (RAP) materials from existing UBBS layers can be used in chip seal and Superpave mixtures. UBBS millings were studied with two different polymer-modified emulsions to assess their performance as precoated aggregates in chip seal. The ASTM D7000-04 sweep test was used to assess chip retention of UBBS millings. Three different mix designs were developed for both 12.5-mm and 9.5-mm nominal maximum aggregate size (NMAS)Superpave mixtures using a PG 70-22 asphalt binder and three different percentages (0%, 10%, and 20%) of reclaimed UBBS materials. The designed Superpave mixes were then tested for performance in terms of rutting and stripping using the Hamburg wheel tracking device (HWTD)and moisture sensitivity by modified Lottman tests. Sweep test results showed that UBBS millings did not improve chip retention. Superpave mix design data indicated volumetric properties of Superpave mixes with UBBS millings met all requirements specified by KDOT. HWTD and modified Lottman test results indicated all designed mixes performed better with the addition of UBBS millings as RAP materials. Field performance of UBBS projects was also evaluated. It was found that pavements treated with UBBS showed high variability in service life with majority serving six years. Before and after (BAA) studies showed that UBBS reduces pavement roughness, transverse and fatigue cracking one year after the treatment. However, no consistent improvement in rutting condition was found.
Fatigue Characteristics Of Field Hma Surface Mixtures Containing Recycled Asphalt Pavement Rap
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Author :
language : en
Publisher:
Release Date : 2006
Fatigue Characteristics Of Field Hma Surface Mixtures Containing Recycled Asphalt Pavement Rap written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2006 with categories.
The use of the Reclaimed Asphalt Pavement (RAP) in asphalt mixes has existed for sometime. Experience has shown that recycling of asphalt pavements is highly beneficial from a technical, economical, and environmental perspective. Some of the main advantages of utilizing the RAP include conservation of asphalt and aggregate resources, conservation of energy, and reduction of construction costs. This report is mainly focused on field study of fatigue and rheological properties of asphalt mixtures with inclusion of different (0,10,20,30) percent of RAP. The objective of this study is to determine what maximum percent of RAP can be introduced into the Tennessee Department of Transportation (TDOT) mixture without affecting mixture properties. Surface mixtures meeting the TDOT "D" mix criteria were evaluated at 0, 10, 20, and 30 percent of screened RAP materials. During the field study two mixes were evaluated (limestone and gravel) with two different types of binder (PG 64-22 and PG 76-22). Fatigue characteristics as well as the mixture properties were tested and evaluated. Tests used for fatigue evaluation of HMA mixture included indirect tensile strength, semi-circular bending, and beam fatigue tests. From this study it was concluded that the inclusion of RAP discarded material, as well as long-term aging, will generally influence the stiffness of the mixture and in return affect its resistance to fatigue cracking. It was also noted that the fatigue properties of the mixtures with 30 percent of RAP material drastically changed the fatigue characteristics as compared to 0, 10, and 20 percent of RAP mixtures. At the higher percentages of RAP the mixture becomes stiffer and fatigue characteristics of the RAP mixture are compromised by adding RAP. Based on the results of the field mixtures, up to 20 percent RAP can be used in TDOT surface mixtures without compromising the fatigue properties of the asphalt mixture.
Innovative Evaluation Of Recycled Asphalt Pavement Rap Use In Slurry Seal Applications
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Author : Hao Ye
language : en
Publisher:
Release Date : 2021
Innovative Evaluation Of Recycled Asphalt Pavement Rap Use In Slurry Seal Applications written by Hao Ye and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with Electronic dissertations categories.
Slurry seal is a surface treatment method that is used to extend the life of asphalt pavements. By sealing the surface from environmental effects (e.g., water penetration and ultraviolet light etc.), slurry seal retards aging (embrittlement) and prevents raveling. Slurry seal is a mixture of Aggregate/Reclaimed Asphalt Pavement (RAP), Asphalt Emulsion and Mineral fillers. To evaluate the potential performance of a slurry seal mixture, multiple traditional tests are conducted, such as Mix Time Test, Cohesion Test, Consistency Test, Wet Stripping Test, Wet Track Abrasion Test (WTAT), Sand Adhesion Test and Classification Compatibility Test. These tests are typically run to determine a slurry seal mixture formula (mixture design). In this study, a comprehensive experimental program was undertaken to compare the performances of slurry seal mixtures made with 100% RAP (Recycled Asphalt Pavement) and virgin (VG) aggregates. The tests included traditional tests such as residual binder content, mix time, cohesion, consistency, wet-abrasion, wet-stripping, integrity/compatibility tests. In addition, two new testing protocols were introduced to assess the abrasion, raveling and rutting resistance of the slurry seal mixtures using the Hamburg Wheel Tracking (HWT) device. It was observed that the slurry seals made with 100% RAP generally performed as good as or better than the slurry seals made with virgin aggregates.
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.
Assessing Increased Use Of Reclaimed Asphalt Pavement In Asphalt Mixtures
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Author : Harikrishnan Nair
language : en
Publisher:
Release Date : 2019
Assessing Increased Use Of Reclaimed Asphalt Pavement In Asphalt Mixtures written by Harikrishnan Nair and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with Asphalt concrete categories.
In 2007, the Virginia Department of Transportation (VDOT) introduced specifications to allow asphalt surface mixtures to have up to 30% reclaimed asphalt pavement (RAP) without a change in the virgin binder grade. Since 2007, increasing material costs and a growing awareness of the quantity of RAP available for use have sparked interest in allowing asphalt mixtures to have a higher percentage of RAP. By 2013, VDOT had begun to consider the feasibility of allowing the use of surface mixtures with up to 45% RAP, and several trial sections were constructed containing mixtures with 20%, 30%, 40%, and 45% RAP for evaluation. This report presents the initial construction and laboratory performance data and discusses the lessons learned from these trials. In general, mixtures containing up to 45% RAP can be designed, produced, and constructed if proper procedures are followed and attention to detail is paid during design, production, and construction. As expected, all high RAP mixtures (i.e., mixtures containing >30% RAP) showed excellent rutting resistance based on laboratory testing. Laboratory performance testing indicated that the cracking resistance of high RAP mixtures depends on mixture and binder stiffness. The early field performance (2 to 3 years) of high RAP mixtures showed excellent rutting resistance and low values for the international roughness index, indicating smooth pavement. No premature cracks were observed in the high RAP sections. However, continued monitoring of these field sections is required to evaluate the long-term field performance.
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."--
Investigation Of Binder Aging And Mixture Performance In Service Reclaimed Asphalt Pavement Mixtures
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Author : Stacey D. Diefenderfer
language : en
Publisher:
Release Date : 2018
Investigation Of Binder Aging And Mixture Performance In Service Reclaimed Asphalt Pavement Mixtures written by Stacey D. Diefenderfer and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with Asphalt concrete--Addititves categories.
In 2007, the Virginia Department of Transportation piloted a specification allowing up to 30% reclaimed asphalt pavement (RAP) in certain dense-graded asphalt surface mixtures while changing virgin binder grade requirements. The change affected only mixtures requiring an end binder grade of either PG 64-22 or PG 70-22. For mixtures specifying PG 64-22 binder, the virgin binder grade at RAP contents of 30% or less was no longer required to change. For mixtures specifying PG 70-22 binder, the virgin binder grade at RAP contents of 21% to 30% was no longer required to change from PG 64-22 to PG 64-28. Prior to this, both types of surface mixtures were allowed to contain only up to 20% RAP before binder grade adjustments were required. An initial laboratory study of mixtures produced under the pilot specification indicated that there were no significant differences for fatigue, rutting, and susceptibility to moisture between the higher content (21% to 30%) RAP mixtures and comparison mixtures (20% RAP or less). The current study evaluated the in-service performance of these mixtures after approximately 7 years and encompassed field visits and a laboratory investigation of a sample of 23 in-service pavements used in the initial laboratory evaluation. Cores were collected from each site and used to evaluate the binder and mixture properties. These data were compared to data from the original construction, when available, to assess the changes in the mixtures over time. Historical performance and maintenance data were also collected and evaluated to investigate the long-term performance characteristics of the sites. Laboratory testing, including dynamic modulus determination, repeated load permanent deformation analysis, and extracted binder grading and analysis, consistently showed no trends in the results with regard to RAP content. Overlay test results were influenced by more than just RAP (air-void content, etc.), and therefore no trend directly related to RAP content was shown. No trends in field performance could be determined because of the underlying structural conditions. Individual locations were found to show better or worse pavement performance, but this was attributed primarily to structural differences in the pavements and preexisting conditions. Surface deterioration observed in numerous test sections included fatigue cracking, longitudinal cracking, transverse cracking, raveling, and potholes. Binder analysis indicated that depth within a layer (in this case, top half versus bottom half) significantly affects binder properties, with stiffness decreasing with depth. However, increasing RAP contents appeared to mitigate the differences between the top half and bottom half of layers, possibly because of the preexisting aged composition of the RAP and its influence on the virgin binder properties.
Evaluation Of The Mmls3 For Accelerated Wearing Of Asphalt Pavement Mixtures Containing Carbonate Aggregates
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Author : Cristian Druta
language : en
Publisher:
Release Date : 2014
Evaluation Of The Mmls3 For Accelerated Wearing Of Asphalt Pavement Mixtures Containing Carbonate Aggregates written by Cristian Druta and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014 with Aggregates (Building materials) categories.
The purpose of this study was to develop an accelerated wearing protocol for assessing the susceptibility of asphalt surface mixtures to polishing. This was the second phase of the study. The first phase focused on assessing the characteristics of selected carbonate aggregates available in Virginia that are normally classified as polishing and thus not considered suitable for use in pavements except for those roads with an average daily traffic of less than 750 vehicles per day. The selection of aggregates used in pavements is critical in producing surfaces that will continue to provide good skid resistance through a lengthy service life.The specifications of the Virginia Department of Transportation (VDOT) call for non-polishing aggregate for use in most surface layers. The study was aimed at making use of locally available polishing aggregates that can reduce the cost of asphalt mixtures while maintaining satisfactory wearing and skid characteristics of the pavements. The objectives of the research were (1) to evaluate the polishing/wear features of mixtures containing limestone aggregate in the laboratory using an accelerated method; (2) to compare friction properties of the laboratory-polished specimens with actual pavement friction measurements; and (3) to compare friction properties of mixtures containing carbonate rock or blends with those of mixtures with non-carbonate rocks.The study included three types of aggregates, i.e., limestone, quartzite, and granite, and blends of these aggregates. The surface mixtures studied were conventional SM-9.5 and SM-12.5 mixtures containing various percentages of limestone, limestone recycled asphalt pavement, and limestone-granite/quartzite blends. The suggested test protocol to evaluate the polishing of asphalt concrete specimens prepared in the laboratory was developed using the third-scale model mobile load simulator (MMLS3). The MMLS3 is capable of applying realistic rolling wheel contact stresses similar to those on highways from the moving traffic.The skid resistance, friction, and texture of actual pavement surfaces and laboratory-fabricated specimens were measured after different polishing intervals. Skid resistance and frictional characteristics were measured by the British pendulum tester, dynamic friction tester, and locked-wheel skid tester; the circular texture meter was used to measure surface macrotexture. Results showed that the MMLS3 can be used to simulate traffic wearing of asphalt concrete specimens of different shapes and sizes in the laboratory including core specimens removed from existing pavements and that the BPT is effective in characterizing changes in friction on specimens that are subjected to simulated trafficking via the MMLS3. Further, test specimens should have a high initial macrotexture and mixtures should have good stability so that the wearing effects are focused on the aggregates. The study recommends that the Virginia Center for Transportation Innovation and Research (VCTIR) work with Virginia Tech and VDOTs western districts to design and conduct an experiment to explore a series of carbonate / non-carbonate aggregate blends for asphalt mixtures and that the mixture gradations be designed to prevent the absence of macrotexture from impacting the ability to measure the polish of the coarse aggregate structure of the experimental mixtures. VCTIR should purchase tires with different tread patterns and try them on the MMLS3 to evaluate the polishing rate of specimens in more detail.