Effect of Blending Degree between Virgin and Aged Binder on Pavement Performance of Recycled Asphalt Mixture with High RAP Content

Xu, Ying; Chou, Zhijing; Li, Yunze; Ji, Jie; Xu, Sheng

doi:10.1155/2019/5741642

Cited by 13 publications

(3 citation statements)

References 15 publications

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“…Noferini et al [14] revealed that increasing the RAP percentage in the asphalt mixes caused more interactions between RAP binder and VAB, which increased the stiffnesses of the EABs. The 100% blending, full blending, between RAP binder and VAB did not reach, even so, the researchers [15] tried different RAP percentages and mixing temperatures. Thus, the full blending is a theoretical assumption that was not achieved.…”

Section: Introductionmentioning

confidence: 99%

Interactions between RAP and virgin asphalt binders in field, plant, and lab mixes

Deef-Allah¹,

Abdelrahman²

2022

World J. Adv. Res. Rev.

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Reclaimed asphalt pavement (RAP) has been used in asphalt mixes for several years in the United States. However, the interactions between the RAP binder and the virgin asphalt binder (VAB) need further investigations. Thus, the main objective of this study was to explore the rheological and chemical properties of extracted asphalt binders (EABs) from plant, field, and lab mixes. The plant mixes were collected from behind the paver, reheated to the compaction temperature, and compacted in the lab. The field mixes were collected as cores within two weeks after the end of the construction process. The lab mixes were fabricated in the lab using the same materials used in the plant and field mixes. The mixes contained high asphalt binder replacement percentages by RAP, which were greater than 30%. The EABs were treated as rolling thin film oven aged VABs (RTFO AVABs). The rheological properties of EABs and RTFO AVABs were analyzed using temperature sweep, frequency sweep, and multiple stress creep recovery tests. Chemical investigations of EABs and RTFO AVABs were carried out using Fourier transform infrared spectroscopy and thermogravimetric analysis. The EABs from plant or lab mixes showed higher stiffnesses than EABs from field mixes. This occurred because of the extra heating that was implemented for the plant mixes before the compaction in the lab, which caused more interactions between the RAP binder and VABs. The fabrication mechanism, mixing and short-term aging processes, used in lab mixes caused more interactions between RAP binder and VABs than in the field mixes.

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Section: Introductionmentioning

confidence: 99%

Interactions between RAP and virgin asphalt binders in field, plant, and lab mixes

Deef-Allah¹,

Abdelrahman²

2022

World J. Adv. Res. Rev.

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“…These aspects are analyzed individually in other scientific papers, while this study presents a comprehensive analysis of all above-mentioned aspects, which is a particularity of the applied methodology. RAP material performances are highlighted in previous researches/studies for both types of origin source, namely unique source or single project site [1][2][3][4][5], as well as multiple sources or project sites [6][7][8][9][10][11][12] collected using milling or other techniques or produced in laboratory after applying long-term aging techniques [13]. Thus, RAP obtained from unique or multiple sources presents significant inhomogeneity and is prepared with pre-processing techniques such as screening, sieving, crushing, storing separately according to its gradation stockpiles [14,15], or even mixing and storing in hybrid RAP stockpiles [16] suitable for further use in a new asphalt mixture.…”

Section: Introductionmentioning

confidence: 99%

An Analysis of Reclaimed Asphalt Pavement from a Single Source—Case Study: A Secondary Road in Romania

2022

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The paper presents a comprehensive analysis on reclaimed asphalt pavement (RAP) milling material collected from a single source, namely from a secondary road in Romania, county road DJ109. The following characteristics are investigated: particle size, binder content, material variability and uniformity, and the clustering phenomena. Variability is demonstrated using the results of particle size gradation and binder content. The coefficient of uniformity and the coefficient of curvature demonstrate that the RAP used in this research is a well-graded material. However, the visual analyses conducted on RAP highlight the presence of RAP particle agglomeration and the need for further testing. The study presents three different experimental phases: (i) RAP-milling old asphalt pavement, RAP; (ii) RAP milling after binder extraction, RAPabe; and (iii) RAP after Los Angeles crushing, RAPac. After processing, the coarse part (C) had a great influence on the fine part (F), and F/C ratio increased, respectively, from 0.4 to 1.5 and 1.61. Material variability on the extended site, the difference between the design values and particle size, as well as the existing clustering process indicated that RAP material collected from secondary roads must be pre-processed prior to its storage and reuse in the recycling process. Considering that secondary roads represent 71% of the overall network of asphalt course roads in Romania, and around 24,000 km of roads are in need of at least extensive maintenance (wearing asphalt courses) or rehabilitation, RAP is a highly recyclable material. Therefore, this study provides advice and guidance for re-using RAP in new pavement mixtures.

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“…e surface aging degree of RAP is usually different from that of the RAP internal [5][6][7]. It was found that there was a big difference between the recycled asphalt and the asphalt because the mineral powder can absorb certain components in the asphalt [8].…”

Section: Introductionmentioning

confidence: 99%

Adhesion Improvement between RAP and Emulsified Asphalt by Modifying the Surface Characteristics of RAP

Wang

Guo

et al. 2020

Advances in Materials Science and Engineering

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Recycled asphalt pavement (RAP) can be used in highway engineering again by cold recycled technology. Due to the aged asphalt on the surface of RAP, some problems such as poor adhesion between emulsified asphalt and RAP and the low properties of emulsified asphalt recycling mixture are easy to occur. This work aims at analyzing the aging degree of asphalt from RAP surface and improving the poor adhesion between RAP and emulsified asphalt by modifying the surface characteristics of RAP. In this work, a new device was designed to delaminate off the asphalt on the surface of RAP. The aging degree of asphalt at different layers was studied then by physical properties and molecular weight distribution. Slurry of hydrated lime (Ca(OH)2) (S-Ca) and slurry of silane coupling agent (SCA) modified Ca(OH)2 (S-Si-Ca) were used to modify the asphalt on the surface of RAP, respectively. The adhesion between emulsified asphalt and RAP was studied by contact angle and boiling method. Results show that the asphalt on the RAP surface can be successfully stripped into four layers through the self-designed RAP delaminating and stripping device. The aging degree of asphalt wrapped around the surface of the RAP showed a tendency to be gradually severe from outside to inside. However, asphalt at the innermost layer (L4) shows abnormal situation due to the fact that the light components are absorbed by the aggregate. In addition, reasonable dosage of SCA is determined as 3.0% in Ca(OH)2 powder mass. Both S-Ca and S-Si-Ca can effectively reduce the contact angle and thus improve the adhesion between emulsified asphalt and RAP. Moreover, S-Si-Ca possesses the most obvious modification effect attributed to the formation of asphalt-SCA-Ca(OH)2 structure.

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Effect of Blending Degree between Virgin and Aged Binder on Pavement Performance of Recycled Asphalt Mixture with High RAP Content

Cited by 13 publications

References 15 publications

Interactions between RAP and virgin asphalt binders in field, plant, and lab mixes

Interactions between RAP and virgin asphalt binders in field, plant, and lab mixes

An Analysis of Reclaimed Asphalt Pavement from a Single Source—Case Study: A Secondary Road in Romania

Adhesion Improvement between RAP and Emulsified Asphalt by Modifying the Surface Characteristics of RAP

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