Download or read book Influence of High RAP on Binder Properties in Hot Mix Asphalt of Northeast written by Donatas Zvirblis and published by . This book was released on 2014 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: The impact of recycled asphalt pavement (RAP) materials on pavement performance is an important topic of study in the asphalt industry due to environmental and cost benefits. A major issue with RAP is that many agencies are still reluctant to allow producers to use more than 10 to 20 percent RAP because of concerns that mixtures with higher RAP contents will be too stiff, less workable and prone to field failures. However, the recent increases in the cost of asphalt binder and the shrinking supplies of quality aggregate has made the use of higher RAP content in hot mix asphalt (HMA) mixtures a priority for the industry. In this study, eighteen plant produced mixtures were obtained from three locations in the Northeast: New York, New Hampshire and Vermont. These mixtures were produced using different RAP contents of 0%, 20%, 30% and 40%. The eighteen mixtures were carefully extracted using American Association of State Highway and Transportation (AASHTO) T164 method "A" using trichloroethyleneand recovered with AASHTO T170 procedure. The recovered binder was then tested using Direct Shear Rheometer (DSR) and Bending Beam Rheometer (BBR) with AASHTO T315 and T313 procedures respectively. The results obtained from these tests were used to determine the continuous grade of the binders. They were then analyzed and compared to one another. Master curves were created for each recovered binder with RHEA and the data obtained from DSR frequency sweet sequence with a 4mm plate. The data recovered from master curves were used to plot black space and, crossover frequency and R-value graphs to show age hardening of binder. This paper investigates the influence of high RAP on asphalt binder stiffness and ductility.
Download or read book Impact of High RAP Content on Structural and Performance Properties of Asphalt Mixtures written by Imad L. Al-Qadi and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Improved Mix Design Evaluation and Materials Management Practices for Hot Mix Asphalt with High Reclaimed Asphalt Pavement Content written by Randy Clark West and published by Transportation Research Board. This book was released on 2013 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Investigation of Low and High temperature Properties of Plant produced RAP Mixtures written by Rebecca McDaniel and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report provides analysis of the results of testing plant-produced hot mix asphalt (HMA) containing various levels of RAP and different grades of virgin binder. The study was undertaken initially to examine the effects of reclaimed asphalt pavement (RAP) on low-temperature properties of mixtures. In phase I of the study, mixes produced by one contractor in 2006 were tested. The results suggest that the addition of RAP stiffened the mix, but probably not to the extent expected based upon linear blending. There is evidence from other research that also suggests that there are cases when linear blending does not apply. Consequently, in phase II of the project, four more contractors replicated the experiment in their HMA plants. The objectives of the study were also expanded to include an evaluation of the extent of blending of the RAP and virgin binders in plant-produced mixtures.
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 Investigation of Low and High temperature Properties of Plant produced RAP Mixtures written by Rebecca McDaniel and published by . This book was released on 2012 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report provides analysis of the results of testing plant-produced hot mix asphalt (HMA) containing various levels of RAP and different grades of virgin binder. The study was undertaken initially to examine the effects of reclaimed asphalt pavement (RAP) on low-temperature properties of mixtures. In phase I of the study, mixes produced by one contractor in 2006 were tested. The results suggest that the addition of RAP stiffened the mix, but probably not to the extent expected based upon linear blending. There is evidence from other research that also suggests that there are cases when linear blending does not apply. Consequently, in phase II of the project, four more contractors replicated the experiment in their HMA plants. The objectives of the study were also expanded to include an evaluation of the extent of blending of the RAP and virgin binders in plant-produced mixtures.
Download or read book Asphalt Pavements written by Y. Richard Kim and published by CRC Press. This book was released on 2014-11-06 with total page 1966 pages. Available in PDF, EPUB and Kindle. Book excerpt: Asphalt Pavements contains the proceedings of the International Conference on Asphalt Pavements (Raleigh, North Carolina, USA, 1-5 June 2014), and discusses recent advances in theory and practice in asphalt materials and pavements. The contributions cover a wide range of topics:- Environmental protection and socio-economic impacts- Additives and mo
Download or read book Superpave Mix Design written by Asphalt Institute and published by . This book was released on 2001-01-01 with total page 102 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 Evaluating the Effects of Recycling Agents on Asphalt Mixtures with High RAS and RAP Binder Ratios written by Amy Epps Martin and published by . This book was released on 2020 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: "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."--
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 Investigation of Binder Rheology and Performance Outcomes of Recycled Hot mix Asphalt Using Different Rejuvenation Agents written by Kerry Jean King and published by . This book was released on 2015 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: The research presented in this thesis investigated the effect of various rejuvenation agents on the performance of hot-mix asphalt (HMA) surfacing mixes containing high levels of recycled asphalt pavement (RAP) material (30%). The research aimed to develop testing methodologies for evaluating the mechanical performance properties of HMA mixes and for the characterisation of extracted binder properties. The methodologies were used determine the effects of various rejuvenators on the mechanical performance properties and binder properties fundamental to the long-term performance of pavement surfaces. A testing methodology was developed to investigate the performance properties of five HMA mixes including four mixes that were rejuvenated using different rejuvenation agents and one control. The mechanical testing methodology provided a comprehensive assessment of mix properties that are fundamental to the long-term performance of recycled pavements. A methodology for the characterisation of extracted binders was developed to evaluate properties that had a significant effect on the performance of the binder and therefore the overall mix. The binder properties were compared to results obtained from mechanical performance tests to establish a relationship between binder rejuvenation and performance observations. The results obtained from mechanical testing demonstrated that the cracking resistance of recycled mixes could be significantly improved through the use of rejuvenation agents. Rejuvenation also decreased the stiffness of the mix and had a negative effect on the resistance of a mix to permanent deformation. From the characterisation of the binder, it was found that rejuvenation agents altered the rheological properties of the binder but did not have a notable effect on chemical composition. The rheological performance parameters of the binder correlated to the mix performance observed from mechanical tests. Overall this research has shown that rejuvenation agents can be utilised to enhance the performance of recycled mixes by restoring binder properties.
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 Effect of Reclaimed Asphalt Pavement on Ontario Hot Mix Asphalt Performance written by Xiomara A. Sanchez-Castillo and published by . This book was released on 2014 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Use of High volume Reclaimed Asphalt Pavement RAP for Asphalt Pavement Rehabilitation written by Nassim Sabahfar and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Because of recent rises in asphalt binder prices, state agencies and contractors are now willing to use higher volumes of reclaimed asphalt pavement (RAP). In this project, the effects of increasing RAP percentage and using fractionated RAP (FRAP) in hot-mix asphalt (HMA) mixtures have been studied. Fractionation involved processing and separating of RAP materials into at least two sizes, typically a coarse fraction and a fine fraction. This study evaluated the effects of increasing the proportions of RAP and FRAP on moisture resistance, rutting, and fatigue cracking of Superpave mixtures. Furthermore, the effect of using different sources of RAP in the mix has been investigated. HMA mixtures with five varying RAP and FRAP contents (20, 30, and 40% RAP, and 30 and 40% FRAP) were studied. The Hamburg wheel-tracking device (HWTD) test (TEX-242-F), the Kansas standard test method no. 56 (KT-56), or modified Lottman test, and the dynamic modulus test (AASHTO TP: 62-03) were used to predict moisture damage, rutting potential, and fatigue cracking resistance of the mixes. HMA specimens were made based on Superpave HMA mix design criteria for 12.5-mm (1/2-inch) nominal maximum aggregate size (NMAS) and compacted using the Superpave gyratory compactor. For the first source of RAP, results of this study showed that although mixture performance declined as the percentage of RAP increased, mixtures with even 40% RAP met minimum performance requirements. The second source of RAP, however, almost failed to meet minimum requirements even at 20% RAP. Results proved the maximum percentage of RAP allowed in the mix is highly influenced by its source. Although some improvements have been observed, especially for the second source of RAP, when RAP is compared to FRAP, FRAP does not seem to considerably affect performance of the HMA mixture.
Download or read book Effect of Bio binders on Binder and Mix Properties with High Rap Content written by Rajib Chandra Saha and published by . This book was released on 2017 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Material Characterization of Alaskan Asphalt Mixtures Containing Reclaimed Asphalt Pavement RAP written by Beaux M. Kemp and published by . This book was released on 2016 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recycled asphalt pavement (RAP) material has been combined with hot-mix asphalt (HMA) paving for several decades to reduce construction costs and environmental impacts. In Alaska, the HMA specification allows up to 15% RAP for Type-II A mixes (typically used in wearing courses) and 25% for Type II-B mixes (used in wearing or base courses). Highway construction projects statewide are expected to see an increase in the use of RAP in future mix designs. Pavement engineers use mechanistic procedures (e.g. Alaska Flexible Pavement Design software and Mechanistic-Empirical Pavement Design Guide) to develop flexible pavement design alternatives. These procedures require material engineering properties as an input source. Consequently, it is essential to properly establish the engineering properties of HMA mixtures containing RAP. In order to characterize Alaskan HMA materials containing RAP, this study evaluated 11 HMA mixtures comprised of three typical Alaskan asphalt binders (PG 52-28, PG 58-34 and PG 52-40) containing 0%, 25% and 35% RAP that were either produced in the lab or a hot-plant (i.e. collected from actual paving projects in Alaska). Various binder and mix properties were determined including; true high binder grades, complex shear modulus (G*) and phase angle (delta) at high performance temperatures, as well as asphalt mixture performance tests (AMPT); dynamic modulus (E*) and flow number (FN). The original (h-based) and the modified (G*-based) Witczak (E*) predictive models were evaluated for these mixtures based on job mix formulae availability for use in mechanistic design procedures. It was found that the incorporation of RAP into Alaskan HMA increased E* and FN of the mixtures, which indicates that the addition of RAP increased the stiffness and rutting resistance of the mixtures tested. A local calibration of the Witczak predictive models may be required for increased accuracy of E* predictions. For Alaskan conditions, a savings of $13.60/ton of mix was estimated for a 25% RAP mix. For an 18-feet wide one lane-mile of HMA mat, it is estimated to have a 21% savings in the 25% RAP mix compared to the conventional virgin (no RAP) mix.
