Download or read book Pavement Performance of Asphalt Surface Course Containing Reclaimed Asphalt Pavement RAP written by Xudong Hu and published by . This book was released on 2012 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reclaimed asphalt pavement (RAP) provides many advantages. The performance of a provincial road with an asphalt surface course containing RAP in Zhejiang, China was evaluated. The surface course was prepared by central plant hot mix recycling and virgin asphalt concrete. An AC-13 was chosen as gradation design in all mixes. The performance of asphalt mixture (containing 0 %, 10 %, 20 %, and 30 % RAP) was evaluated in the laboratory for fatigue resistance condition, moisture susceptibility, high-temperature stability, and low-temperature anti-cracking. Based on the laboratory results, the provincial road was constructed consisting of three sections (corresponding to 0 %, 10 %, and 20 % RAP content) in surface course with a 30-mm depth. The field site has been inspected and observed for 4 years. The field testing included deflection, skid resistance, permeable performance, and evenness evaluations. The laboratory test results show that all the testing indices satisfied the demand of the specifications, except moisture susceptibility and low temperature anti-cracking performance of the recycled asphalt concrete, including 30 % RAP. The inspection data proved that a small percentage of RAP unaffected the surface course performance, but RAP ratios greater than 20 % are not suitable in the mainline for high-volume roadways.

Download or read book Guide for Pavement Friction written by and published by AASHTO. This book was released on 2008 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report contains guidelines and recommendations for managing and designing for friction on highway pavements. The contents of this report will be of interest to highway materials, construction, pavement management, safety, design, and research engineers, as well as others concerned with the friction and related surface characteristics of highway pavements.

Download or read book Evaluation of Reclaimed Asphalt Pavement for Surface Mixtures written by Rebecca McDaniel and published by Purdue University Press. This book was released on 2012-08-01 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

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 Improving Durability of Asphalt Mixes Produced with Reclaimed Asphalt Pavement Rap by Enhancing Binder Blending written by Hawraa Kadhim and published by . This book was released on 2019 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reclaimed Asphalt Pavement (RAP) has been favoured over virgin materials in the light of the unstable cost of virgin asphalt binders, shortage of quality aggregates, and compelling need to preserve the environment and natural resources. Mixes containing up to 20% RAP are commonly considered to have similar behaviour to virgin mixes. However, during the production process of HMA with RAP, the blending between aged and virgin binders would be partial, which would create heterogeneity in distribution of the aged recycled binder and the soft virgin binder in the HMA-RAP mixes. Hence, it is important to control the blending process between old and new binders to obtain more homogenous mix. Therefore, the main objectives of this research are to examine the kinematics of blending of aged and virgin binders by considering the time-temperature effect during mixing and silo-storage, and assess the thermo-mechanical behaviour of Hot Mix Asphalt (HMA) containing RAP at different blending states. The asphalt mixes used in this research were produced and collected at two plants (Plant 1) and (Plant 2) located in Ontario, Canada. Two Marshall mixes were produced and collected from Plant 1 including a surface course HL-3 containing 15 percent RAP and a base course HL-8 containing 30 percent RAP. These mixes were labelled as 1HL-3 and 1HL-8 respectively. In addition, two Marshall mixes were produced and collected from Plant 2 including a surface course HL-3 containing 20 percent RAP and a base course HL-8 containing 40 percent RAP. These mixes were labelled as 2HL-3 and 2HL-8 respectively. To investigate the impact of storage time on the blending progress and achieving a cohesive final binder, the mix samples were collected as a function of storage time in the silo. The first sampling was done immediately after production (t = 0-hour), and then at several time intervals of silo-storage; i.e., at 1, 4, 8, and 12 hours. In case of Plant 2, the samples were additionally collected after 24-hour of storage time. All samples were then kept in a storage room at 7ʻC until the day of compaction to minimize any further blending between aged and virgin binder. To understand the blending phenomena and its effect on the performance of the pavement, a multi-scale investigation is carried out. The blending was examined in terms of micro-mechanical and rheological properties. The microstructure of the blending zones were examined under The Environmental Scanning Electron Microscope (ESEM). In addition the effect of the silo-storage time on the rheology of the binders was investigated. The results indicate that increasing the interaction time and temperature between the aged and virgin binder significantly results in a better blending. The performance of RAP-HMA with respect to the silo-storage time was examined using Dynamic Modules Test, Thermal Stress Restrained Specimen Test (TSRST), Rutting Test, and Flexural Beam Fatigue Test. The experimental data indicates that samples collected after 12-hour of silo storage exhibited a reduction in the stiffness due to better blending of aged and virgin binder. In addition, the 12-hour samples showed enhancement in their fracture temperature, rutting depth, and fatigue life, accompanied with a better blending between their aged and virgin binder. On the other hand, the samples that collected after 24-hour silo-storage had a higher stiffness in comparison with the 8 and 12-hour samples. Moreover, the AASHTOWare Pavement Mechanistic-Empirical Design was utilized to examine the effect of the 12-hour silo-storage time on the long term performance of the pavements. Four pavement structures have been designed for this purpose. These pavements have the same structure of their granular A, granular B, and the subgrade. Yet, the first layer (surface course and base course) is a silo-storage time-dependent. The long-term field performance prediction indicates a slight improvement with the 12-hour pavements (Plant1 12hrs and Plant2 12hrs). However, it should be noted that AASHTOWare Pavement Mechanistic-Empirical Design does not appear to properly capture the effect of blending in the pavement performance. The collected experimental evidences unveils correlations between time-temperature effects and mixture performance. Based on these findings, the research provides practical recommendations to the professionals of the Canadian asphalt industry for a better use of RAP. Ultimately, this research recommends a 12-hour silo-storage time for the RAP-HMA for better performance and durability of the mixes.

Download or read book Eleventh International Conference on the Bearing Capacity of Roads Railways and Airfields written by Inge Hoff and published by CRC Press. This book was released on 2021-11-10 with total page 501 pages. Available in PDF, EPUB and Kindle. Book excerpt: Innovations in Road, Railway and Airfield Bearing Capacity – Volume 1 comprises the first part of contributions to the 11th International Conference on Bearing Capacity of Roads, Railways and Airfields (2022). In anticipation of the event, it unveils state-of-the-art information and research on the latest policies, traffic loading measurements, in-situ measurements and condition surveys, functional testing, deflection measurement evaluation, structural performance prediction for pavements and tracks, new construction and rehabilitation design systems, frost affected areas, drainage and environmental effects, reinforcement, traditional and recycled materials, full scale testing and on case histories of road, railways and airfields. This edited work is intended for a global audience of road, railway and airfield engineers, researchers and consultants, as well as building and maintenance companies looking to further upgrade their practices in the field.

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.

Download or read book Performance Evaluation of Reclaimed Asphalt Pavement RAP as a Dense Graded Aggregate Base Course DGABC written by Frank Palise and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Reclaimed Asphalt and Performance Based Evaluation of Its Use in Recycled Mixtures written by Jesse David Doyle and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Evaluation of High Percentage Recycled Asphalt Pavement as Base Course Materials written by Mengqi Wu and published by . This book was released on 2011 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Field Performance of Maintenance Treatments Constructed with Reclaimed Asphalt Pavement RAP written by Cindy K. Estakhri and published by . This book was released on 1994 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Assessing Increased Use of Reclaimed Asphalt Pavement in Asphalt Mixtures written by Harikrishnan Nair and published by . This book was released on 2019 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

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 The Use of Reclaimed Asphalt Pavement in New SUPERPAVE Asphalt Concrete Mixtures written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: While the research and development of the SUPERPAVE asphalt mixture design and analysis system did address the use of polymer modified asphalt binders in the specification of material performance properties, no recommendations or procedural guidelines were given for the use of recycled materials. The use of recycled asphalt pavements (RAP) in new paving mixtures is not an innovative idea. RAP has been called one of the most recycled materials in the world, and its use in paving mixtures has been shown to have environmental, economic and performance benefits. In this study, four different RAP stockpiles were sampled and the characteristics of each RAP material were investigated in terms of binder content, aggregate gradation and the rheologic characteristics of the reclaimed RAP binder. The reclaimed RAP binders were blended with several different virgin performance graded binders in order to determine how RAP binder concentration affected the stiffness and performance grade of the RAP -- virgin binder blends. Recommendations were made on how to select virgin binder grade andor RAP concentration combinations to fulfill a project's binder grading requirements. The effects of RAP were also investigated in terms mixture design, and recommendations were made with regards to material handling and specimen fabrication procedures. Asphalt concrete mixtures containing RAP were characterized in terms of stiffness and resistance to plastic strain using SUPERPAVE testing methods, and the results of these tests were compared to those of virgin material mixtures. Assuming a simulated pavement cross section and traffic loading, the results of this performance testing were used in performance prediction models to estimate how pavements constructed with RAP would perform compared to those made from 100% virgin materials. The predicted performance of pavements containing up to 40% RAP (by weight) was found to be similar or slightly better than that of virgin material pavements.

Download or read book Bituminous Mixtures and Pavements VII written by A.F. Nikolaides and published by CRC Press. This book was released on 2019-05-24 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt: Highway engineers are facing the challenge not only to design and construct sustainable and safe pavements properly and economically. This implies a thorough understanding of materials behaviour, their appropriate use in the continuously changing environment, and implementation of constantly improved technologies and methodologies. Bituminous Mixtures and Pavements VII contains more than 100 contributions that were presented at the 7th International Conference ‘Bituminous Mixtures and Pavements’ (7ICONFBMP, Thessaloniki, Greece 12-14 June 2019). The papers cover a wide range of topics: - Bituminous binders - Aggregates, unbound layers and subgrade - Bituminous mixtures (Hot, Warm and Cold) - Pavements (Design, Construction, Maintenance, Sustainability, Energy and environment consideration) - Pavement management - Pavement recycling - Geosynthetics - Pavement assessment, surface characteristics and safety - Posters Bituminous Mixtures and Pavements VII reflects recent advances in highway materials technology and pavement engineering, and will be of interest to academics and professionals interested or involved in these areas.

Download or read book Performance Assessment of Asphalt Mixes Containing Reclaimed Asphalt Pavement and Tire Rubber written by Shawn Shiangfeng Hung and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The pavement community, including both agencies and industries, is moving toward more sustainable pavement designs and pavement network management. Increasing amounts of recycled materials, both reclaimed asphalt pavement (RAP) and recycled tire rubber, are expected to be used in new pavement construction projects in the future to reduce the use of virgin binder and aggregates. The main concern of using recycled materials in new asphalt pavement is the potential negative effect on the performance. Thus, the primary objective of this dissertation is to improve the current laboratory testing technologies and performance assessment approaches for characterizing the performance-related properties of asphalt mixes containing recycled materials and to improve understanding of how these properties affect the performance of asphalt pavements so that they can be designed and constructed better. A major challenge regarding the use of high RAP content mixes is the differences in the rheological properties of the virgin binder (mixes without RAP) and the blended binder (mixes with RAP). Traditionally, binder blending charts are used to determine the appropriate RAP content in asphalt mixes and the selection of virgin binder grade as part of the Superpave volumetric mix design procedures when RAP is incorporated in the mix. However, producing mixes based on blending charts that require testing of extracted and recovered RAP binders is expensive and hazardous. An alternative test approach for binder blending charts using fine aggregate matrix (FAM) mix testing is presented in this dissertation. The results demonstrated that the proposed approach could estimate the blended binder intermediate and low performance grading temperatures within ±3°C of the measured blended binder performance grading temperatures. Even though the proposed approach is not as accurate as the blending chart method (within ±2°C), it provides both cost and environmental benefits. Currently, the Superpave Performance Grading (PG) system cannot not be used to evaluate the performance-related properties of asphalt rubber binders produced using larger crumb rubber particles (maximum particle size passing 2.36 mm sieve) due to the limitations of parallel plate geometry. With the consideration of more open-graded or gap-graded rubberized hot mix asphalt (RHMA-O and RHMA-G) projects in the future, it is important to be able to perform Superpave PG testing on asphalt rubber binder and to establish performance-based contract acceptance criteria for the production of asphalt rubber binders. The test results indicated that the concentric cylinder geometry is an appropriate alternative geometry to parallel plates for quantifying the properties of asphalt rubber binders and specifically for assessing the high-temperature performance properties of binders containing crumb rubber particles larger than 250 [mu]m. Concerns have been raised with regard to incorporating reclaimed rubberized asphalt pavement (RRAP) into dense-graded new hot mix asphalt (HMA-DG) and RAP into new RHMA-G since the interactions between the virgin binder, age-hardened binder, and recycled tire rubber could considerably affect the rutting, fatigue cracking, and thermal cracking performances of new HMA-DG and RHMA-G. The fundamental differences between RAP and RRAP were identified and the performance of new mixes that contain these recycled materials were evaluated in this study. The experimental results showed that adding RRAP to HMA-DG mixes is ideal to resist rutting and low-temperature cracking based on the changes in mix stiffness. The HMA-DG mixes containing RRAP are better at resisting high tensile strain loadings than mixes containing RAP. In addition, adding RAP to RHMA-G mixes improves the rutting performance but diminishes the cracking performance, and potentially negating the benefits of selecting RHMA-G as an overlay to retard the rate of reflection cracking. Lastly, the effects of rest periods on asphalt fatigue performance considering asphalt thixotropy, non-linearity, self-heating, self-cooling, and steric hardening were also investigated in this research. The experimental test results showed that asphalt thixotropic softening and other biasing effects control the first 10 to 15 percent decrease in stiffness for unmodified binders and 15 to 35 percent decrease in stiffness for modified binders under cyclic loading, and this decrease in stiffness can be recovered with the introduction of rest periods. This means that most of the repeated loadings applied to test specimens within the thixotropic softening range do not caused any fatigue damage but only softening of the materials. Thus, by providing sufficient rest periods within the thixotropic softening range can effectively improve asphalt fatigue performance. Both the thixotropic softening range and the required time for thixotropic recovery (i.e., rest periods) need to be considered in asphalt fatigue test and mechanistic-empirical (ME) design for better evaluation of the true fatigue performance.

Download or read book Reclaimed Asphalt Pavement written by Imad L. Al-Qadi and published by . This book was released on 2007 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: Illinois has been recycling Reclaimed Asphalt Pavement (RAP) material into hot-mix asphalt (HMA) since 1980, this research project seeks to determine the appropriate level of contribution that should be given to the residual asphalt binder in RAP.