Multiscale Characterization of Aging and Rejuvenation in Asphalt Binder Blends with High RAP Contents

Abdelaziz, Amal; Masad, Eyad; Martin, Amy Epps; Mercado, Edith Arámbula; Bajaj, Akash

doi:10.1061/(asce)mt.1943-5533.0003910

Cited by 27 publications

(2 citation statements)

References 45 publications

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“…As shown in Figure 8 a, the aged asphalt’s roughness increases due to decreased compatibility between the wax crystal and polar matrix phase. Compared to the aged asphalt, due to the addition of 70% raw asphalt, the roughness of the recycled asphalt binder is reduced, and its surface is smoothed [ 31 ]. As the recycling times increase, the roughness in recycled asphalt changes slightly.…”

Section: Resultsmentioning

confidence: 99%

Effect of Re-Recycling on Rheology and Microstructure of Asphalt Binder

Chen

Zhu

et al. 2022

Materials

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Currently, aged recycled asphalt pavements have re-recycling demands, but the evolution mechanism of re-recycled asphalt binder properties is still unclear. Therefore, this study analyzes the rheological properties and microstructure of re-recycled asphalt by dynamic shear rheometer (DSR), bending beams rheometer (BBR), atomic force microscope (AFM), and Fourier transform infrared spectroscopy (FTIR). The macro performance results show that re-recycling improves high-temperature performance and reduces fatigue and low-temperature performance. In addition, the aged re-recycled asphalt’s ΔTc ≤ −2.5 °C, has a risk of low-temperature cracking. The micro results show that the adhesion between asphalt and aggregate decreases as the recycling times increase; the re-recycled asphalt mixture has a greater adhesion cracking risk. Some macro–micro experimental results are correlated. Aging accelerates the decay of rheological properties of re-recycled asphalt by increasing the microscopic roughness and carbonyl index of re-recycled asphalt. It indicates that re-recycling reduces the aging resistance of asphalt. Furthermore, the properties of recycled asphalt are strongly correlated with aging functional groups, roughness, and surface energy; the microstructural changes significantly influence the rheology properties of asphalt.

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Section: Resultsmentioning

confidence: 99%

Effect of Re-Recycling on Rheology and Microstructure of Asphalt Binder

Chen

Zhu

et al. 2022

Materials

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“…Yet, there are different sets of conditions deployed for mixing the rejuvenator, new and old binders, and all aimed to reach a homogeneous and stable blend (Zaumanis et al, 2020). The temperature varies from 130 C (Li et al, 2021) to 160 C (Elkashef et al, 2018; Pradhan and Sahoo, 2020; Abdelaziz et al, 2021); the mixing was done by high shear (Elkashef et al, 2017;Elkashef et al, 2018), mechanical mixer (Pradhan and Sahoo, 2020) and hand stirring (Yu et al, 2014;Abdelaziz et al, 2021); and, of course, the mixing time (15 min to 2 h) and rotational speed are prone to much variation. So, the main goal of this study is nding the set of mixing conditions that gives an asphalt binder blend representing the asphalt binder inside the asphalt mixture with very high RAP content.…”

Section: Introductionmentioning

confidence: 99%

Rheological Comparison Between Blended Asphalt Binders and Extracted and Recovered Asphalt Binder From Rejuvenated Asphalt Mixture With Very High Rap Content

Imaninasab,

Loria-Salazar,

Carter

2023

Preprint

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Efficient rejuvenation of the RAP’s binder facilitates the use of higher RAP contents. Assessing the efficiency requires evaluating the right blend of the rejuvenator, new and old binder that represents the real binder blend inside the asphalt mixture. Extracted and recovered (E&R) binder from the rejuvenated asphalt mixtures containing RAP is the best practice to obtain the existing blend of the rejuvenator, new and old binder. However, Extraction and recovery is not a common practice to study rejuvenation efficiency since it is time-consuming and energy-demanding with exposure to hazardous chemicals. Instead, blending rejuvenator, new binder and the E&R binder from RAP under appropriate blending conditions limits the extraction and recovery to RAP, and minimizes efforts for studying rejuvenation efficiency. This study aims to find the blending conditions under which the blend of the rejuvenator, new and RAP binder resembles the E&R binder from asphalt mixture rheologically. The rheological properties of three binder blends prepared under intense (IB), medium (MB) and low blending (LB) conditions were compared with those of the E&R binder. Performance grade (PG), rutting potential, fatigue resistance and behavioral characteristics are the rheological properties for making comparison. It was found that IB and MB are good representative of the E&R binder with regard to PG and PG + designation. In addition to IB and MB, LB can be a surrogate for the PAV-aged E&R binder. Also, any blending conditions between MB and IB for rutting potential and characterization are recommended.

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