Influences of Preheating Temperature of RAP on Properties of Hot-Mix Recycled Asphalt Mixture PDF Download

Author: T. Ma
Publisher:
ISBN:
Category : Agglomerate
Languages : en
Pages : 8

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Book Description
This study analyzed the agglomerate characteristics of reclaimed asphalt pavement (RAP) material and evaluated the influences of the preheating temperature of RAP on the properties of recycled asphalt mixture. Specific surface-area analysis was conducted to reveal the agglomerate characteristics of RAP. A triaxial shear test was conducted for RAP with different preheating conditions to evaluate the dispersion characteristics of RAP and its influences on RAP property. Freeze-thaw splitting test, wheel tracking test, and low-temperature bending-beam test were conducted to evaluate the influences by preheating temperature of RAP on the properties of recycled asphalt mixture. It is found that, because of the agglomerates of RAP, the specific surface area of RAP is much lower than that of real aggregates. Sufficient preheating of RAP can promote the dispersion of RAP by activating the flowability of aged asphalt in RAP. The properties of recycled asphalt mixture keep improving with the increase of the preheating temperature of RAP. There is a minimum-temperature limit for RAP preheating to guarantee the properties of recycled asphalt mixture.

Author: Hervé Di Benedetto
Publisher: Springer Nature
ISBN: 3030464555
Category : Technology & Engineering
Languages : en
Pages : 1806

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Book Description
This volume highlights the latest advances, innovations, and applications in bituminous materials and structures and asphalt pavement technology, as presented by leading international researchers and engineers at the RILEM International Symposium on Bituminous Materials (ISBM), held in Lyon, France on December 14-16, 2020. The symposium represents a joint effort of three RILEM Technical Committees from Cluster F: 264-RAP “Asphalt Pavement Recycling”, 272-PIM “Phase and Interphase Behaviour of Bituminous Materials”, and 278-CHA “Crack-Healing of Asphalt Pavement Materials”. It covers a diverse range of topics concerning bituminous materials (bitumen, mastics, mixtures) and road, railway and airport pavement structures, including: recycling, phase and interphase behaviour, cracking and healing, modification and innovative materials, durability and environmental aspects, testing and modelling, multi-scale properties, surface characteristics, structure performance, modelling and design, non-destructive testing, back-analysis, and Life Cycle Assessment. The contributions, which were selected by means of a rigorous international peer-review process, present a wealth of exciting ideas that will open novel research directions and foster new multidisciplinary collaborations.

Author: Zhanping You
Publisher: MDPI
ISBN: 3038428892
Category : Technology & Engineering
Languages : en
Pages : 431

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Book Description
This book is a printed edition of the Special Issue "Advanced Asphalt Materials and Paving Technologies" that was published in Applied Sciences

Author: Viết Hưng Nguyễn
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
The primary work reported in this thesis is concerned mainly with the effects of different mixing methods and RAP materials on homogeneity and mechanical properties of hot recycled asphalt mixtures. The recycled asphalt mixture conforms to the requirement of BS 4987-1 (2005) for dense bitumen macadam size 10 mm (DBM 10 mm). The proportion of RAP in the recycled mixture is 40%. RAP materials are artificially aged and processed in the laboratory to prevent the variability of RAP gradation, bitumen content, and the origin. Laboratory RAP is also used to assure that every single RAP particle is an agglomerate of RAP aggregate and binder. The mixing procedures include Black Rock (BR), Complete Blending (CB), the SHRP procedure, and a newly developed field simulation method (FS). The primary difference between these methods is the mixing mechanism. The BR case implies the situation in which there is completely no interaction between RAP and virgin binder. On the contrary, RAP and virgin binder are fully interacted in the CB case. The mixing procedures for BR and CB cases conform to those for conventional asphalt mixtures. However, the bitumen for BR case is pure virgin bitumen. In addition, the bitumen for CB is the blend between RAP and virgin binder. The RAP/virgin binder proportion is 4/6. In the SHRP method, RAP is preheated at 110oC for two hours before being mixed with virgin aggregate and binder for 2 minutes at 130oC. In the FS method on the contrary, the mixing procedure duplicates what occurs in the asphalt mixing plant. RAP is mixed with superheated virgin aggregate (215oC) for different durations before this combination is blended with virgin bitumen for 2 minutes at 130oC. The RAP/superheated virgin aggregate mixing duration starts from short mixing time where RAP still exists at approximately original size and gradually increases until the change in RAP lump size is insignificant. Depending on the size of RAP used, RAP/superheated virgin aggregate mixing duration varies from 1 to 8 minutes. The homogeneity of hot recycled asphalt mixture is examined by using virgin binder with a different colour from that of RAP binder. The colour of virgin binder is obtained by mixing clear binder (Shell Mexphalt C 160/220 Pen) with iron oxide pigment. The proportion of pigment is 10% by weight of the binder making this binder red. The use of virgin binder with different colour from that of RAP binder helps to clearly differentiate the locations of RAP and virgin materials. Surfaces of slices cut from compacted recycled specimens are photographed by digital camera. The analysis of these surfaces in vertical order allows the locations of RAP material to be qualitatively identified in a 3D manner. Stiffness modulus values of samples for homogeneity assessment are also determined by indirect tensile stiffness test. The stiffness test is carried out in four directions along the circumference of each specimen with 45o angular increments. The experimental results show that the stiffness measurement in four directions can indicate the heterogeneity of recycled mixture. The variation in stiffness values in different measured directions will be substantial for heterogeneous mixtures and minor in the case where recycled mixtures are homogeneous. The results indicate there are mutual relations between mixing effort, homogeneity, and stiffness values of recycled asphalt mixtures. The longer mixing time will enhance the homogeneity and reduce the variation in stiffness values of recycled mixture. In addition, as more RAP and virgin binder are incorporated, the stiffness values of recycled mixture generally increase once the mixing time is extended. As the clear binder is dyed red by 10% by weight of iron oxide, the proportion of the pigment certainly alters the flow characteristic of binder. This might affect the mixing process and rejuvenating effect between virgin and aged binder. Therefore, the effects of mixing methods and RAP sizes on mechanical performance of hot recycled asphalt mixtures are further investigated using normal straight run bitumen 160/220 Pen as virgin binder. The assessment indicators include stiffness modulus, resistance to fatigue damage, and resistance to permanent deformation. The experimental results indicate that the conventional laboratory mixing method (SHRP) tends to overestimate the mechanical properties of recycled asphalt mixture. The long RAP preheating time that never exists in the industry coincidentally enhances the reaction between RAP and virgin binder. The long RAP preheating time also slightly alters the properties of RAP binder. For the FS method, the increase in mixing duration significantly improves the homogeneity level of recycled mixtures. The homogeneity level is also substantially affected by the size of RAP material. For the same mixing effort, the mixtures comprised of small RAP are generally more homogeneous than those made from larger RAP. The more homogeneous the mixture, the more interaction between RAP and virgin binder. Therefore, recycled mixtures become stiffer and have better resistance to permanent deformation and fatigue failure. A slightly linear increase in stiffness can result in an exponential increase in fatigue life of the recycled mixture. The mechanical properties including stiffness modulus, resistance to fatigue damage, and resistance to permanent deformation of hot recycled asphalt mixtures are not similar to those of the BR or CB mixtures, even at the favourable condition where RAP is preheated for 2 hours at 110oC in the SHRP method and 8 minutes mixing duration in the FS method. This implies that RAP does not act as Black Rock. In addition, the assumption that RAP and virgin binder are fully blended also never exists in the recycled asphalt production process.

Author: Shaopeng Wu
Publisher: MDPI
ISBN: 3039210149
Category : Technology & Engineering
Languages : en
Pages : 256

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Book Description
Construction materials are the most widely used materials for civil infrastructure in our daily lives. However, from an environmental point of view, they consume a huge amount of natural resources and generate the majority of greenhouse gasses. Therefore, many new and novel technologies for designing environmentally friendly construction materials have been developed recently. This Special Issue, “Environment-Friendly Construction Materials”, has been proposed and organized as a means to present recent developments in the field of construction materials. It covers a wide range of selected topics on construction materials.

Author: Sandra Erkens
Publisher: CRC Press
ISBN: 1317285522
Category : Technology & Engineering
Languages : en
Pages : 212

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Book Description
Functional Pavement Design is a collections of 186 papers from 27 different countries, which were presented at the 4th Chinese-European Workshops (CEW) on Functional Pavement Design (Delft, the Netherlands, 29 June-1 July 2016). The focus of the CEW series is on field tests, laboratory test methods and advanced analysis techniques, and cover analysis, material development and production, experimental characterization, design and construction of pavements. The main areas covered by the book include: - Flexible pavements - Pavement and bitumen - Pavement performance and LCCA - Pavement structures - Pavements and environment - Pavements and innovation - Rigid pavements - Safety - Traffic engineering Functional Pavement Design is for contributing to the establishment of a new generation of pavement design methodologies in which rational mechanics principles, advanced constitutive models and advanced material characterization techniques shall constitute the backbone of the design process. The book will be much of interest to professionals and academics in pavement engineering and related disciplines.

Author: Rebecca McDaniel
Publisher:
ISBN:
Category : Pavements, Asphalt
Languages : en
Pages : 0

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Book Description
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.

Author: Rebecca McDaniel
Publisher:
ISBN:
Category : Pavements, Asphalt
Languages : en
Pages : 95

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Book Description
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.

Author: Xinjun Li
Publisher:
ISBN:
Category : Binders (Materials)
Languages : en
Pages : 63

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Book Description
Recycled Asphalt Pavement (RAP) has been used in Minnesota for over 25 years. The most commonly used method is to mill material from an existing pavement and incorporate it into a new asphalt mix. Previous experience and specifications allow various RAP percentages depending on the traffic level. Past research has also shown the effects of RAP on both the high- and low-temperature properties of asphalt cement and the asphalt mixtures. Therefore, it becomes an important priority to study and determine the effects various types and percentages of RAP have on the asphalt cement and mixture quality. This will result in a rational design for asphalt mixture that contain RAP and could change Mn/DOT's asphalt specification.

Author: Randy Clark West
Publisher: Transportation Research Board
ISBN: 0309259134
Category : Pavements, Asphalt
Languages : en
Pages : 162

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Book Description
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.