Use of Data from Specific Pavement Studies Experiment 5 in the Long-Term Pavement Performance Program to Compare Virgin and Recycled Asphalt Pavements

West, Randy; Michael, Jenna; Turochy, Rod E; Maghsoodloo, Saeed

doi:10.3141/2208-11

Cited by 37 publications

(25 citation statements)

References 3 publications

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“…Field studies show similar trends: application of up to 30% RAP in mixtures showed equal or better performance than virgin mixes, though it was noted that the material performed worse with respect to fatigue (7). In another field study (7,8) it was found that warm-mix asphalt (WMA) containing RAP is softer (lower dynamic modulus) than a HMA containing the same amount of RAP. The authors attributed this to incomplete blending of the RAP and virgin binders.…”

Section: Introductionmentioning

confidence: 88%

First Observation of Blending-Zone Morphology at Interface of Reclaimed Asphalt Binder and Virgin Bitumen

Nahar

Mohajeri

Schmets

et al. 2013

Transportation Research Record: Journal of the Transportation R

114

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One of the challenges in designing recycled asphalt mixtures with a high amount of reclaimed asphalt pavement (RAP) is estimating the blending degree between RAP binder and added virgin bitumen. The extent of blending is crucial because asphalt concrete response is influenced by the final binder properties. This paper focuses on the evaluation of interaction and extent of blending between RAP binder and virgin bitumen by studying the microstructures of the blending zone with atomic force microscopy (AFM). AFM is used to probe the change of microstructural properties from a RAP binder and virgin bitumen to the blending zone of these two. Averaged microstructural properties have been observed in thin-film blends of RAP binder and pure bitumen. The morphology of the blending zone (spatial extent of about 50 μm) exhibits domains of a wide range of microstructure sizes (160 nm to 2.07 μm) and can be considered to be a completely blended new material that has been observed directly for the first time. The fully blended binder properties are found to be between those of the two individual binders, as could be inferred from the averaged microstructural properties derived from AFM images of the blending zone. This finding is also consistent with the results of mechanical tests by dynamic shear rheometer on the same materials. Finally, a design formula is proposed that relates the spatial dimensions of the blending zone to temperature and mixing time, which will eventually allow the results of this study to be extended from small-length scales up to the engineering level.

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Section: Introductionmentioning

confidence: 88%

First Observation of Blending-Zone Morphology at Interface of Reclaimed Asphalt Binder and Virgin Bitumen

Nahar

Mohajeri

Schmets

et al. 2013

Transportation Research Record: Journal of the Transportation R

114

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“…overlays constructed from both virgin and 30% RAP mixtures on milled and nonmilled surfaces in a variety of climates. Overall, the long-term field performance of asphalt mixtures containing up to 30% RAP was similar to that of asphalt mixtures with virgin materials (West et al 2011;Carvalho et al 2010). A detailed analysis of cracking progression in the LTPP SPS-5 virgin and 30% RAP sections in New Jersey showed that cracks appeared at approximately the same time but progressed faster in the RAP sections.…”

Section: Introductionmentioning

confidence: 68%

“…To address this concern, several national research efforts have been conducted. Analyses (West et al 2011;Carvalho et al 2010;Bennert and Maher 2013) were conducted on field performance data from pavement sections in the Specific Pavement Studies 5 (SPS-5) of the Long-Term Pavement Performance (LTPP) program to determine the effect of RAP on long-term field performance. The SPS-5 pavement sections consisted of 5-and 12.7-cm (2-and 5-in.)…”

Section: Introductionmentioning

confidence: 99%

Effect of a Recycling Agent on the Performance of High-RAP and High-RAS Mixtures: Field and Lab Experiments

Tran

Julian

Taylor

et al. 2017

J. Mater. Civ. Eng.

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Reclaimed asphalt pavement (RAP) and recycled asphalt shingles (RAS) have been increasingly used in asphalt mixtures. The use of RAP and RAS in asphalt mixtures not only reduces the consumption of virgin materials, conserves energy, and protects the environment but also improves the rutting resistance of asphalt pavements. However, as more recycled materials are used in asphalt mixtures, there is increasing concern over their potential negative effects on the mix cracking resistance. To improve the cracking resistance of asphalt mixtures with high RAP/RAS contents, one of the approaches considered is using recycling agents to potentially restore performance properties of the aged binder. This project was conducted to evaluate the effect of a recycling agent (RA), known as Hydrogreen, on the long-term field performance of high RAP and RAS mixes. The field study consisted of three test sections, each constructed by placing a dense-graded surface lift at a depth of 4.5 cm (1.75 in.) on SR 7 near Harrisonville, Missouri, in August 2013. The three mixes placed in the three test sections included: (1) a control mix containing 30% RAP using an SBS-modified PG 70-22 binder with no RA; (2) a 40% RAP mix using the same PG 70-22 binder with RA; and (3) a 25% RAP and 5% RAS mix using a neat PG 64-22 with RA. This paper presents data collected during the construction of the test sections, laboratory performance testing results, and early field performance. The research results showed that the recycling agent could be used in the 40% RAP and 25% RAP and 5% RAS mixes to achieve similar construction quality, laboratory performance, and early field performance to the 30% RAP control mix. As these sections are still in service, it is recommended that they continue to be monitored in order to evaluate their long-term performance.

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“…The findings observed from Figures 10 to 12 in terms of material type, asphalt layer thickness and milling are compared with a study on SPS-5 pavement performance (West et al, 2011). This study used SPS-5 performance data to investigate the effects of overlay rehabilitation.…”

Section: Comparison With Field Performancementioning

confidence: 99%

Kinetics-based aging evaluation of in-service recycled asphalt pavement

Luo

Zhang

et al. 2018

Journal of Cleaner Production

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Reclaimed asphalt pavement (RAP) is a type of material that already suffers long-term aging in the field, so its aging characteristics become prominent since they are closely related to premature distresses and longevity of recycled pavements. While most of investigations of RAP mixtures are carried out in the laboratory, this study focuses on in situ aging of asphalt pavements with RAP overlays. A kinetics-based aging modeling approach is proposed to analyze and quantify long-term field aging of RAP overlays using the Falling Weight Deflectometer (FWD) data and climate data. The kinetics-based approach contains a modulus aging model with kinetic parameters (e.g. aging activation energy) for asphalt mixtures. Eight asphalt overlays are selected with different mixtures (RAP and virgin), thickness (50 mm and 125 mm), and surface preparation (milling and no milling). An asphalt pavement with an overlay has a composite aging process since the aging speeds of different asphalt layers are different. Thus an approach to separate the FWD modulus is developed in order to obtain the actual aging behaviors and properties of the overlay. By applying the kinetics-based modeling to the separated FWD moduli, the aging activation energies of both the overlays and old asphalt layers are determined. It is found that the RAP overlay has the highest aging activation energies and slowest aging rates among the RAP overlay, virgin overlay, and old asphalt layer for the selected pavements. It also reveals through the aging activation energy that the thick overlays age slower than thin ones, and the overlays on milled pavements age slower than those placed without milling. The findings in terms of the aging activation energy can be used to explain the difference in the field performance of overlay pavement sections.

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Use of Data from Specific Pavement Studies Experiment 5 in the Long-Term Pavement Performance Program to Compare Virgin and Recycled Asphalt Pavements

Cited by 37 publications

References 3 publications

First Observation of Blending-Zone Morphology at Interface of Reclaimed Asphalt Binder and Virgin Bitumen

First Observation of Blending-Zone Morphology at Interface of Reclaimed Asphalt Binder and Virgin Bitumen

Effect of a Recycling Agent on the Performance of High-RAP and High-RAS Mixtures: Field and Lab Experiments

Kinetics-based aging evaluation of in-service recycled asphalt pavement

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