Pavement Performance of Asphalt Surface Course Containing Reclaimed Asphalt Pavement (RAP)

Pavement Performance of Asphalt Surface Course Containing Reclaimed Asphalt Pavement (RAP) PDF Author: Xudong Hu
Publisher:
ISBN:
Category : Bridge design
Languages : en
Pages : 7

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Book Description
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.

Pavement Performance of Asphalt Surface Course Containing Reclaimed Asphalt Pavement (RAP)

Pavement Performance of Asphalt Surface Course Containing Reclaimed Asphalt Pavement (RAP) PDF Author: Xudong Hu
Publisher:
ISBN:
Category : Bridge design
Languages : en
Pages : 7

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Book Description
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.

Superpave Mix Design

Superpave Mix Design PDF Author: Asphalt Institute
Publisher:
ISBN: 9781934154175
Category : Asphalt
Languages : en
Pages : 102

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Book Description


Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields

Eleventh International Conference on the Bearing Capacity of Roads, Railways and Airfields PDF Author: Inge Hoff
Publisher: CRC Press
ISBN: 1000533336
Category : Technology & Engineering
Languages : en
Pages : 501

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Book Description
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.

Evaluation of Reclaimed Asphalt Pavement for Surface Mixtures

Evaluation of Reclaimed Asphalt Pavement for Surface Mixtures PDF Author: Rebecca McDaniel
Publisher: Purdue University Press
ISBN: 9781622602131
Category :
Languages : en
Pages : 44

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Book Description
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.

Improving Durability of Asphalt Mixes Produced with Reclaimed Asphalt Pavement (Rap) by Enhancing Binder Blending

Improving Durability of Asphalt Mixes Produced with Reclaimed Asphalt Pavement (Rap) by Enhancing Binder Blending PDF Author: Hawraa Kadhim
Publisher:
ISBN:
Category : Asphalt concrete
Languages : en
Pages : 158

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Book Description
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.

Recycling Materials for Highways

Recycling Materials for Highways PDF Author: National Research Council (U.S.). Transportation Research Board
Publisher: Transportation Research Board National Research
ISBN:
Category : Nature
Languages : en
Pages : 64

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Book Description
"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.

Performance Evaluation of Reclaimed Asphalt Pavement (RAP) as a Dense Graded Aggregate Base Course (DGABC)

Performance Evaluation of Reclaimed Asphalt Pavement (RAP) as a Dense Graded Aggregate Base Course (DGABC) PDF Author: Frank Palise
Publisher:
ISBN:
Category : Pavements, Asphalt
Languages : en
Pages :

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Characterization of Reclaimed Asphalt and Performance Based Evaluation of Its Use in Recycled Mixtures

Characterization of Reclaimed Asphalt and Performance Based Evaluation of Its Use in Recycled Mixtures PDF Author: Jesse David Doyle
Publisher:
ISBN:
Category : Asphalt
Languages : en
Pages :

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Book Description
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 High Percentage Recycled Asphalt Pavement as Base Course Materials

Evaluation of High Percentage Recycled Asphalt Pavement as Base Course Materials PDF Author: Mengqi Wu
Publisher:
ISBN:
Category : Asphalt
Languages : en
Pages : 145

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Book Description


Guide for Pavement Friction

Guide for Pavement Friction PDF Author:
Publisher: AASHTO
ISBN: 1560514280
Category : Pavements
Languages : en
Pages : 87

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Book Description
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.