Download or read book Effect of Recovered Binders from Recycled Shingles and Increased RAP Percentages on Resultant Binder PG written by Ramon Francis Bonaquist and published by . This book was released on 2011 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book WisDOT Research Program written by and published by . This book was released on 2010 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Guidelines and Specifications for Use of WMA Technology in Delivering HMA Products Inclusive of Non conventional Mixtures Such as SMA s and Mixtures with RAP and RAS Content written by Ramon Bonaquist and published by . This book was released on 2014 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Recycled Shingles and Increased RAP Percentages written by Ramon Francis Bonaquist and published by . This book was released on 2012 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt: As asphalt binder becomes more expensive, the use of recycled asphalt materials becomes more attractive. Recycled asphalt pavement (RAP) and recycled asphalt shingles (RAS) offer a partial substitute for virgin aggregate and binder in asphalt pavement mixtures. Their use reduces the demand on natural resources, energy and landfill space as well as the cost of asphalt mixtures. The Federal Highway Administration increasingly encourages use of this green highway technology.
Download or read book Effect of Recycled Asphalt Shingles RAS on Physical and Chemical Properties of Asphalt Binders written by Umme Amina Mannan and published by . This book was released on 2012 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt: A laboratory study was conducted to evaluate the effect of recycled asphalt shingles (RAS) on the physical and chemical properties of asphalt binders. A virgin asphalt binder meeting the Superpave specifications for PG 58-28 was mixed with varying percentages (0, 5, 7, and 10%) of RAS binder recovered from post-manufactured asphalt shingles. The physical properties of the blended binders were measured using the rotational viscometer (RV), dynamic shear rheometer (DSR), multiple stress creep recovery (MSCR), and bending beam rheometer (BBR) tests. The chemical properties of the binders were determined using the Fourier transform infrared spectrometry (FTIR) and gel-permeation chromatography (GPC) tests. The physical test results showed an improved resistance to permanent deformation (or rutting) with the addition of RAS, but higher susceptibility to early low-temperature (thermal) cracking. The results were inconclusive regarding the fatigue resistance of the RAS-containing asphalt binders. The chemical test results showed an increased level of aging due to the addition of RAS. Higher levels of aging were also observed following the use of the rolling thin film oven (RTFO) and the pressure aging vessel (PAV) tests. There was a modest increase in the level of aging in RTFO-aged binders due to the addition of RAS. However, significantly higher levels of aging were obtained for PAV-aged binders containing higher percentages of RAS, indicating that the addition of RAS will primarily impact the long-term performance of the asphalt binders.
Download or read book Effect of Reclaimed Asphalt Pavement and Recycled Asphalt Shingles on Fracture Tolerance of Asphalt Binders written by Yu Yan and published by . This book was released on 2019 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fracture energy density (FED), which is defined as the energy per unit volume required to initiate fracture, is a key property governing the resistance to fracture of asphalt binders. This study evaluated the effect of reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) on virgin binder FED using the binder fracture energy (BFE) test. The objective was to determine whether RAP and RAS can be used with soft virgin binders to achieve satisfactory fracture tolerance. Experimental factors included two RAP sources, two RAS sources (manufacture waste (MW) shingles and tear-off (TO) shingles), and four virgin binders. BFE tests were conducted on blends of virgin and recovered RAP/RAS binders at two binder replacement rates of 15 % and 30 %. Moreover, the Superpave true grade of RAP/RAS binder blends was determined using the dynamic shear rheometer and bending beam rheometer. Results showed that the use of soft virgin binders effectively compensated for the stiffening effect of RAP/RAS in terms of true grade. The addition of RAP binder and MW shingle binder increased the FED of unmodified binders, whereas the opposite trend was observed for TO shingle binder. Furthermore, great caution should be exercised when using virgin polymer-modified binders because significant reductions in FED were observed when RAP and RAS binder was introduced, possibly because of the dilution of polymer modification in addition to stiffening and embrittlement effects. This study indicated that both RAP and RAS are recyclable, according to the Superpave true grade requirements. However, further research is needed to evaluate the effect of the reduction in binder FED caused by TO shingles on mixture fracture performance before its acceptance in asphalt mixtures.
Download or read book Evaluation of the Combined Effects of Reclaimed Asphalt Pavement RAP Reclaimed Asphalt Shingles RAS and Different Virgin Binder Sources on the Performance of Blended Binders for Mixes with Higher Percentages of RAP and RAS written by M. Z. Alavi and published by . This book was released on 2015 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Impact of Recycled Asphalt Shingles RAS on Asphalt Binder Performance written by and published by . This book was released on 2018 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study evaluated the effect of reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) on virgin binder true grade and fracture energy density (FED).
Download or read book Influence of Recovery Processes on Properties of Binders and Aggregates Recovered from Recycled Asphalt Pavement written by Zahid Hossain and published by . This book was released on 2011 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Usage of recycled asphalt pavement (RAP) in the construction of new pavements has increased in recent years due to the movement to conserve energy and raw materials, and reuse waste materials. To assess the effectiveness of RAP materials in new asphalt mixes, it is important to evaluate the properties of the recovered binders and aggregates. The widely used "Abson" method is employed in this study to recover asphalt binder from RAP. Also, the frequently used "NCAT ignition" method is used to extract aggregates. A laboratory study comprising two field RAP materials, two simulated RAP materials, and corresponding virgin materials was undertaken to assess possible influences of the aforementioned recovery processes. The performance grade (PG) of the recovered binders, and gradation, durability (LAAbrasion and Micro-Deval), specific gravity, sand equivalent, and insoluble residue of the extracted aggregates were evaluated as per the AASHTO and Oklahoma Dept. of Transportation (ODOT) standards. The test results showed that the Abson method notably influenced the critical PG temperatures of the recovered binder. It was also observed that some mechanical properties (durability and sand equivalent) of RAP aggregates were inconsistent with their virgin counterparts. Furthermore, field RAP aggregates showed significant variations in LA Abrasion loss and insoluble residue test results. The findings of this study are expected to be helpful in the evaluation of RAP for reuse in asphalt paving.
Download or read book Fundamental Evaluation of the Interaction Between RAS RAP and Virgin Asphalt Binders written by Munir D. Nazzal and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive laboratory testing program was conducted in this research project to examine the blending between reclaimed asphalt pavement (RAP)/recycled asphalt shingles (RAS) and virgin asphalt binders and to evaluate the factors that may affect fatigue and low-temperature cracking as well as moisture-induced damage in asphalt mixtures prepared using these materials. This project included two parts: a binder study and a mixture study. In the binder study, atomic force microscopy (AFM) was utilized to characterize the micromechanical properties of the interfacial zone that develops between the RAP/RAS binders and the virgin asphalt binders. Three virgin asphalt binders with different performance grades (PG 58-28, PG 64-28, and PG 64-22), three RAP sources, as well as manufacturing waste and tear-off RAS were used in this project. A new sample-preparation procedure was developed to simulate the blending between the RAS/RAP and the virgin asphalt binders that occurs during asphalt mixture production. The micro-structure, stiffness and the adhesive properties along the blending zone were evaluated for different combinations of RAP/RAS binders and virgin binders. In the mixture study, several asphalt mixtures were used to evaluate the effect of the incorporation of RAP and/or RAS on the mix performance, including a control mixture (no RAP or RAS), a mixture containing 30% RAP, a mixture containing 5% tear-off RAS, and a mixture containing 20% RAP and 3% tear-off RAS. All mixtures were designed to meet ODOT specifications for Item 442 (Superpave) Type A for heavy traffic intermediate course asphalt mixes. The resistance of the asphalt mixtures to fatigue cracking was evaluated using the semi-circular bend (SCB) and the indirect tensile strength (IDT) tests. The SCB test was performed using the Illinois Method and the Louisiana Method. In addition the potential for low-temperature cracking was evaluated using the asphalt concrete cracking device (ACCD), and the susceptibility of the asphalt mixtures to moisture-induced damage was evaluated using the AASHTO T 283 (modified Lottman) test. The AFM test results indicated that blending occurred to a varying degree between the RAP binders and the virgin binders for all RAP-virgin binder combinations. The average modulus of the blending zone depended on the properties of the RAP and the virgin binders. For all binders, a reduction in the adhesive bonding energy was also observed in the blending zone due to the presence of RAP. However, the adhesive properties of the blending zone were significantly higher than those in the RAP binders. Statistical analysis also indicated that the stiffness of the interface blending zone is affected by the properties of the RAP and virgin asphalt binders, while the adhesive properties of the interface blending zone is primarily affected by those of virgin binder used. A linear regression model was developed to predict the modulus and adhesive bonding energy of the blending zone in terms of RAP and virgin binder properties. The validation of the regression models suggested that these models can serve as a viable tool in selecting the virgin binder to be used in a RAP mixture based on the properties of the RAP binder. Finally, the AFM imaging and force spectroscopy experiments revealed very limited to no blending between manufacturing waste or tear-off RAS materials and the virgin binders considered. The asphalt mixture test results also showed that the use of tear-off RAS in intermediate asphalt mixes significantly reduced their resistance to low-temperature and fatigue cracking as well as moisture damage, which can be attributed to the limited blending observed in the AFM experiments between the RAS and the virgin asphalt binders.
Download or read book Blending Issues of Hot and Warm Mix Asphalt Containing Recycled Asphalt Pavement and Recycled Asphalt Shingle written by Sheng Zhao (Writer on pavements) and published by . This book was released on 2014 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Long Term Effectiveness of Recycling Agents to Improve Performance Properties of Asphalt Concrete written by Mahsa Tofighian and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recycled materials such as reclaimed asphalt pavement (RAP) have been incorporated into asphalt mixtures for many years. However, their usage has increased over time as they are seen as a way to reduce the cost of asphalt mixtures, save energy, and protect the environment. Similarly, there has been a growing focus on the utilization of recycled asphalt shingles (RAS) in asphalt mixtures, a pursuit undertaken by various state highway agencies. However, unless appropriate precautions are taken, as the proportion of RAP and RAS in the asphalt mixture is raised, the mixture becomes more brittle, leading to a higher risk of cracking and raveling in the asphalt pavement. Furthermore, the mixture becomes less workable and more challenging to compact in the field, increasing the potential for premature field failure. One strategy to incorporate more RAP and RAS into asphalt mixtures involves the use of specialized recycling agents (RAs), known as rejuvenating agents. Over time, asphalt mixtures undergo aging during construction and over the extended service life of asphalt pavements, resulting in the oxidation of the mix and the loss of a significant portion of the maltenes in the binder composition. Maltenes contribute to the softening effect of the binder, and these recycling agents, when used appropriately, are expected to compensate for this reduction in maltenes. The ultimate result of this rebalancing of components is the softening of the aged binder and an improvement in its resistance to cracking. This study investigates the long-term impact of bio-based and petroleum-based recycling agents (RA's) on recycled asphalt binders with varying levels of reclaimed asphalt pavement (RAP) and reclaimed asphalt shingles (RAS) content, specifically low (15%) and high (30%) RAP content and 0% and 5% RAS content. The rejuvenated binders underwent short-term and long-term aging through the use of a Rolling Thin Film Oven (RTFO) and Pressure Aging Vessel (PAV), respectively. The performance characteristics of these modified binders at various aging stages were assessed using a dynamic shear rheometer (DSR) and bending beam rheometer (BBR). The study revealed that all RA's used in this research maintained their effectiveness even after long-term aging, though the degree of effectiveness varied. Additionally, the results indicated that the petroleum-based RA required a higher dosage to achieve the same effect as the bio-based RA's. The findings from this research also demonstrated that when rejuvenators are added to mixtures with a high RAP content or a combination of RAP and RAS, the mixture's performance is enhanced in terms of low-temperature cracking and fatigue cracking. Nevertheless, it is crucial to extend this work to field pilot projects to ensure the effective application of these rejuvenating products.
Download or read book Evaluation of Asphalt Binder and Mixture Properties that Incorporate Reclaimed Asphalt Pavement written by Sang Ki Lee (M.S. in Engineering) and published by . This book was released on 2018 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several private and public agencies are exploring ways in which the use of reclaimed asphalt pavement (RAP) can be increased in the construction of new pavements. However, such an increase must not come at the expense of reduced durability or life cycle cost. The use of RAP is often accompanied by some form of adjustment to the virgin binder that is being used. In Texas, the current practice of incorporating RAP is controlled by a simplified table that lists a substitute binder grade and recycled binder ratio (RBR) when RAP is incorporated in a mix. There are a few shortcomings with this simple approach of specifying a maximum ratio: (1) it does not address the potential difference in the quality of recycled binders from RAP, (2) it may result in the use of substituted binders with little or no polymer (elastomer) and (3) it does not account for the influence of recycling agents. The goal of this study was to evaluate the change in performance of binders and mixtures using different grades of virgin binder and percentages of RAP. Two different Job Mix Formulae (JMF) and corresponding materials were obtained from asphalt plants in the state of Texas. A test matrix was developed to evaluate binders and mixtures with different ratios of recycled binder to virgin binder and different ratios of RAP to virgin material, respectively. The results from this study show that addition of RAP or recycled binder (from RAP) results in an increase in stiffness and resistance to rutting, which was expected. However, the resistance to cracking showed mixed results. The test results also show that the properties of the recycled binder from RAP can vary significantly with source and have a drastic effect on the properties of the binder and mixture.
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 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 Evaluating the Effect of High RAP Content on Asphalt Mixtures and Binders Fatigue Behavior written by Umme Amina Mannan and published by . This book was released on 2018 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the main concerns with the application of reclaimed asphalt pavement (RAP) in the asphalt concrete pavement is fatigue cracking due to the stiffness increase with the addition of aged and stiff RAP binder. The purpose of this study is to evaluate fatigue performance of asphalt binder and mixtures with different RAP percentages (0, 15, 25, 35 and 40 %). Among these, 35 and 40 % RAP mixes are considered as high RAP content. This study describes the results of laboratory fatigue response of asphalt mixtures and extracted binders containing RAP to define the effect of RAP on the fatigue performance. To achieve this objective, mixes and binders were tested using the beam fatigue test and the time-sweep test, respectively. Test results were analyzed using two different fatigue approaches, reduction in stiffness and dissipated energy criteria. Results showed that a higher initial stiffness and initial dissipated energy initiate the fatigue failure faster. Since both binders and mixes show an increase in the stiffness and energy consumed per loading cycle with the addition of RAP, resulting mixes containing higher RAP have a very short fatigue life. Also, the fatigue endurance limit decreases drastically with the addition of RAP in the mix. The results comparing two different RAP sources showed that the RAP source has more prominent effect on the mix fatigue performance than the binder fatigue performance. Finally, the traditional fatigue life prediction model is modified to incorporate the effect of RAP in the fatigue equation. The modified regression model predicted reasonable fatigue life of the mixture with a coefficient of determination (R2) close to 1. The measured and predicted fatigue life results were found close to each other for both mix and binder containing RAP.
Download or read book Recycling Materials for Highways written by National Research Council (U.S.). Transportation Research Board and published by Transportation Research Board National Research. This book was released on 1978 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This synthesis will be of special interest and usefulness to design engineers, materials technologists, and others seeking information on the potential use of recycled materials in design, construction, rehabilitation, and maintenance of pavements, bases, and other components of the highway system. Detailed information is presented on procedures for pavement recycling."--Avant-propos.
