Review From Multiple Perspectives for the State of the Practice on the Use of Recycled Asphalt Materials and Recycling Agents in Asphalt Concrete Surface Mixtures

The objective of this paper is to provide information from multiple perspectives on the current state of the practice with regard to using recycled materials and recycling agents (RAs) in asphalt concrete mixtures. This information was collected through a survey of U.S. transportation agencies and RA suppliers combined with a search of RA-related specifications and pilot projects previously constructed. Moreover, a case study describing the Virginia Department of Transportation’s experience with RAs provides a tangible example of how at least one agency is approaching the potential implementation of these technologies. This practice review was achieved by documenting the experience, lessons learned, and best practices of multiple asphalt experienced contractors and asphalt binder suppliers in the Virginia area. This paper follows a similar survey conducted in 2014 as part of NCHRP 09-58 and provides a second look at the use of RAs across North America. Not all state departments of transportation have experience with using RAs. Factors preventing the use of RAs included specification limitations, lack of expertise in processing recycled materials, supporting data, and negative prior experiences. Developing a performance-based testing framework is mandatory for the successful use of RAs. In general, good and frequent communication with the RA supplier is critical and necessary during the planning stages, the production of mixtures, and the continuous quality control by the supplier to resolve issues when they arise. Finally, a strong quality control and quality assurance-testing program should be implemented to ensure that materials meet the properties needed to produce a good-performing mixture.

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PARTICULARITIES OF HOT-IN-PLACE RECYCLING WITH CHANGING THE ASPHALT CONCRETE MIXTURE AGGREGATE GRADATION

Avtoshliakhovyk Ukrayiny ◽

10.33868/0365-8392-2018-4-256-20-27 ◽

2018 ◽

pp. 20-27

Author(s):

Vasyl Nagaychuk ◽

Sergii Illiash

Keyword(s):

Layer Thickness ◽

Asphalt Concrete ◽

Recycled Aggregate ◽

Concrete Mixture ◽

Concrete Aggregate ◽

Recycled Asphalt ◽

Recycled Materials ◽

Aggregate Gradation ◽

Methods Of Calculation ◽

Concrete Layer

The hot in-place recycling (HIR) belongs to the successful strategies of asphalt concrete pavements rehabilitation that provides effective elimination of such surface defects as cracking, rutting, stripping, raveling, and bleeding including defects caused by the non-conformity of asphalt concrete to the standard specifications. The HIR technologies are divided into four methods: «Reshape», «Repave», «Remix», and «Remix Plus». Among those methods, «Remix» and «Remix Plus» are more complicated technologically and are connected with changing the composition of existed (old) asphalt concrete. The composition of existed asphalt concrete should be corrected through the addition some of new components (aggregates, asphalt binder, rejuvenating agent, or new hot-mixed asphalt concrete mixture) to the hot-milled old asphalt layer. This article is dedicated to the methods of calculation of new and recycled aggregate mixture gradation regarding to the Ukrainian standards. The proposed methods of calculation consider such main peculiarities of HIR-recycled materials and layer design as: 1) old asphalt concrete, particularly its aggregate parts, can used in a non-fractioned form only; 2) HIR-recycled asphalt concrete layer should be designed with or without the maximal layer thickness restriction. The proposed methods also give the possibility to correct the technological process if the calculated amount of new material necessitated to the correction of old asphalt concrete aggregate grading does not allow to maintain the projected layer thickness. The implementation of the proposed technique of calculation of aggregate grading with and without restriction of the maximal thickness of recycled asphalt concrete layer allows enhance quality of recycled materials and promotes the entire adaptation of HIR technologies to the Ukrainian standards. Keywords: hot in-place recycling of asphalt concrete, «Remix», «Remix Plus», recycled asphalt concrete mixture, correction of aggregate gradation.

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Effect of Recycling Rate and Asphalt Binder on the Performance of Recycled Asphalt Concrete for Airport Pavement Rehabilitation

Road Materials and Pavement Design ◽

10.1080/14680629.2009.9690199 ◽

2009 ◽

Vol 10 (2) ◽

pp. 361-371 ◽

Cited By ~ 2

Author(s):

Kai Su ◽

Yoshitaka Hachiya ◽

Ryota Maekawa

Keyword(s):

Asphalt Concrete ◽

Asphalt Binder ◽

Recycling Rate ◽

Recycled Asphalt ◽

Pavement Rehabilitation ◽

Airport Pavement

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Experimental Evaluation of Moisture Damage and Rutting Resistance for SBS Modified Warm Mix Asphalt Incorporating Recycled Asphalt Concrete

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.904.464 ◽

2021 ◽

Vol 904 ◽

pp. 464-469

Author(s):

Mohammed Qadir Ismael

Keyword(s):

Tensile Strength ◽

Asphalt Concrete ◽

Experimental Evaluation ◽

Asphalt Binder ◽

Stability Index ◽

Warm Mix Asphalt ◽

Recycled Asphalt ◽

Moisture Susceptibility ◽

Rutting Resistance ◽

Styrene Butadiene

The efforts embedded in this paper have been devoted to designing, preparing, and testing warm mix asphalt (WMA) mixtures and comparing their behavior against traditional hot mix asphalt mixtures. For WMA preparation, the Sasobit wax additive has been added to a 40/50 asphalt binder with a concentration of 3%. An experimental evaluation has been performed by conducting the Marshall together with volumetric properties, indirect tensile strength, and wheel tracking tests to acquire the tensile strength ratio (TSR), retained stability index (RSI), and rut depth. It was found that the gained benefit of reduction in mixing and compaction temperatures was reversely associated with a noticeable decline in Marshall properties and moisture susceptibility indices designated by TSR, and RSI, and even the rut resistance was adversely affected. Modification of WMA mixtures by 3% of Styrene-Butadiene-Styrene (SBS) polymer coupled with replacement of virgin ingredient by 50% of recycled asphalt concrete granted a 20% and 15% growth in Marshall stability and tensile strength, respectively. Moreover, both TSR and IRS indices have risen to 87% and 90%, respectively associated with a 39% increase in rutting resistance ability.

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Laboratory investigation of the recycled asphalt concrete with stable crumb rubber asphalt binder

Construction and Building Materials ◽

10.1016/j.conbuildmat.2019.01.114 ◽

2019 ◽

Vol 203 ◽

pp. 552-557 ◽

Cited By ~ 56

Author(s):

Xunhao Ding ◽

Luchuan Chen ◽

Tao Ma ◽

Haixia Ma ◽

Linhao Gu ◽

...

Keyword(s):

Laboratory Investigation ◽

Asphalt Concrete ◽

Asphalt Binder ◽

Crumb Rubber ◽

Recycled Asphalt

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A Study of Relationship Between Residual Asphalt in Aggregate Surface and Aging Degree of its Asphalt

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.602-604.985 ◽

2012 ◽

Vol 602-604 ◽

pp. 985-989

Author(s):

Wen Tsung Liu ◽

Ming Ho Tu

Keyword(s):

Asphalt Concrete ◽

Coarse Aggregate ◽

Soxhlet Extraction ◽

Recycled Asphalt ◽

Recycled Materials ◽

The Road ◽

Coarse Aggregates ◽

Processing Techniques ◽

Relationship Of ◽

The Relationship

Abstract. Laying the road, a lot of asphalt mixing plants use recycled asphalt concrete instead of fresh asphalt concrete. The main reason is that the plants don’t need to provide the viscosity inspection when testing because it is not mentioned in the contract. Even if the value of bitumen viscosity is high in the test report, it is difficult to prove effectively whether to join the asphalt recycled materials or not. This study is to explore the relationship between their extraction of bitumen and coarse aggregate cleanliness by Soxhlet extraction from asphalt recycled materials and fresh asphalt concrete. Besides, we look for the differences after washing asphalt. The research focuses on the method to view the number of the cleanliness on the coarse aggregate surface. The coarse aggregates will be divided into four kinds of sieve (3/4 ", 1/2", 3/8 ", # 4) in process. The selected range is by the built-in program of Photoshop_CS3. We determined the percentage of asphalt area on the aggregates in line with the RGB values. We further used the image processing techniques (Matlab program of image analysis) to assess the relationship of the above mention and compared the basic properties of the asphalt.

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Impact of Recycled Materials and Recycling Agents on Asphalt Binder Oxidative Aging Predictions

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198118797205 ◽

2018 ◽

Vol 2672 (28) ◽

pp. 277-289 ◽

Cited By ~ 2

Author(s):

Sara Pournoman ◽

Elie Y. Hajj ◽

Nathan Morian ◽

Amy Epps Martin

Keyword(s):

Asphalt Binder ◽

Asphalt Binders ◽

Complex Nature ◽

Recycled Asphalt ◽

Recycled Materials ◽

Reclaimed Asphalt ◽

Oxidative Aging ◽

Cracking Potential ◽

Binder Oxidation ◽

The Individual

The overall objective of this study was to evaluate the influence of selected recycling agents (RAs) and recycled materials on the development of cracking potential with respect to oxidative aging. Given the complex nature of varying base asphalt binders, recycled materials, whether recycled asphalt pavement (RAP), reclaimed asphalt shingles (RAS), or both, and the complexity of their combined interactions with recycling agents, standard evaluation protocols for binder grading and evaluation may be insufficient. The binder blend aging predictions or oxidation modeling evaluation was introduced as a means to evaluate the combined influence of both binder oxidation kinetics and resulting rheological changes on the measured cracking potential of the various binder blends—that is, Glover–Rowe (G-R) parameter—driven by temperature estimation modeling over simulated in-service durations at example geographic locations. This evaluation has demonstrated the importance of adequate characterization of the specific materials being used in conjunction with selection of the correct dose of the appropriate recycling agent to ensure sufficient resistance to cracking and embrittlement of proposed material combinations. The combined influence of all the interested components did not always add up to the sum of the individual parts, nor are the measured interactions consistent with increased levels of oxidation. Therefore, the prevailing conclusion of the study as a whole indicated that material-specific evaluations are needed to identify the complex interactions taking place within the material combinations of interest, but also multiple levels of aging at appropriate intervals may be necessary for comprehensive characterization.

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A Mechanical Approach to Quantify Blending of Aged Binder from Recycled Materials in New Hot Mix Asphalt Mixtures

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198118787634 ◽

2018 ◽

Vol 2672 (28) ◽

pp. 107-118 ◽

Cited By ~ 3

Author(s):

Milad Zokaei Ashtiani ◽

Walaa S. Mogawer ◽

Alexander J. Austerman

Keyword(s):

Mechanical Performance ◽

Asphalt Binder ◽

Asphalt Mixtures ◽

Point Of View ◽

Asphalt Binders ◽

Master Curves ◽

Recycled Asphalt ◽

Recycled Materials ◽

Performance Point ◽

Aged Binder

In the paving industry, there is increased interest in using recycled materials like recycled asphalt shingles (RAS) and reclaimed asphalt pavements (RAP) due to the valuable asphalt binder contained within them. The major concern with using these materials is that the binder they contain is highly aged, which could lead to reduced mixture durability. Therefore, a method is needed to quantify the extent to which the aged binders from these materials blend with virgin binder when producing mixtures in order to understand better their effects on mixture performance. In this study, a new approach to quantify the amount of blending that occurs between aged RAS and RAP binders and a virgin binder was developed. Asphalt binders were extracted and recovered from RAS and RAP stockpiles and blended with a PG64-28 virgin binder in varying proportions. The master curves of these mixtures were constructed at 20°C. Asphalt mixtures containing different proportions of the same RAS and RAP stockpiles were then designed and the dynamic moduli of the mixtures were measured to construct mixture master curves at 20°C. The binder master curves for each blending proportion were then substituted into a locally calibrated Hirsch model to predict the mixture master curves. Comparison of the measured and predicted mixture master curves suggested that the aged binder from RAS and RAP blends with the virgin binder less than 40% and 60%, respectively. Cracking tests were also conducted to validate the proposed degrees of blending from a mixture mechanical performance point of view.

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