Blending efficiency of Reclaimed Asphalt Pavement: An approach utilizing rheological properties and molecular weight distributions

Bowers, Benjamin F.; Moore, Jason; Huang, Baoshan; Shu, Xiang

doi:10.1016/j.fuel.2014.05.059

Cited by 85 publications

(32 citation statements)

References 12 publications

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“…However, the mastic sample mixed at 160°C, 160_V160/220_60RAP0.2_40 showed characteristics which became closer to 110_V160/220_53BitRAP_47 in terms of "bee" structure sizes and roughness. This may indicate that higher mixing temperature, 160°C, produced better blending between the virgin bitumen and the bitumen from RAP0.2 as reported also by Bowers et al (2014a). Regarding the mixing time, the samples prepared using 70 min of mixing, as did not show significant differences from those prepared using only 20 min.…”

Section: Resultssupporting

confidence: 58%

“…Some of the relevant works are listed below. Using dynamic shear rheometer (DSR) and gel permeation chromatography (GPC) measurements, it was shown that mixing time and mixing temperature influenced the blending state (Bowers et al 2014a). GPC and Fourier transform infrared (FTIR) spectroscopy measurements were combined to determine the blending state in different layers of the bitumen film around the RAP mineral aggregate (Bowers et al 2014b); partial blending occurred in different layers, with the outermost layer being the softest and the innermost layer (closer to the mineral aggregate) the stiffest.…”

Section: Introductionmentioning

confidence: 99%

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Thermal and Water Effects on Virgin Bitumen, Recycled and Mastic Mixtures

2015

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Blending between aged bitumen from reclaimed asphalt pavement (RAP) and virgin bitumen is important in recycled asphalt. In this work, bitumen blends prepared by mixing virgin bitumen and recovered bitumen from RAP, were investigated as well as mastic mixtures prepared by mixing virgin bitumen with RAP. The aim of the study was to investigate the differences between virgin bitumen, bitumen blends containing different amounts of bitumen recovered from RAP, and mastic mixtures, in terms of surface microstructure, rheological properties and wetting behaviour. Thermal studies were carried out using different mixing times, annealing temperatures and cooling rates. The change in the molecular assembly was determined using attenuated total reflectance Fourier transform infrared spectroscopy; surface properties were evaluated using atomic force microscopy and the rheological properties were evaluated using dynamic shear rheometer. It was observed that the shear complex modulus and phase angle as well as the surface properties of the bitumen blends depended on the BitRAP content. The cooling rate of bitumen films influenced strongly the surface properties such as the roughness and size of the so-called "bee" structures as well as the molecular assembly. Additionally, contact angle measurements performed during dispensing of a water drop on the bitumen surface showed that in the presence of water, the viscoelastic bitumen films deformed at the three phase (bitumen-water-vapour) contact line and the deformation was influenced by the cooling rate of the bitumen films.

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Section: Resultssupporting

confidence: 58%

Section: Introductionmentioning

confidence: 99%

Thermal and Water Effects on Virgin Bitumen, Recycled and Mastic Mixtures

2015

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“…However, this level of RAP incorporation was relatively low. Bowers et al [12] studied blending and diffusion between the RAP binder and virgin bitumen using staged extraction to isolate the recovered binder into different layers. Gel Permeation Chromatography and Fourier Transform Infrared Spectroscopy tests were used to study the properties of the binder recovered from different layers, and it was concluded that blending occurs in all binder layers but that it may not be uniform.…”

Section: Introductionmentioning

confidence: 99%

Design considerations of high RAP-content asphalt produced at reduced temperatures

2018

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In many countries recycling of reclaimed asphalt pavement (RAP) for road surface layers is limited to a maximum of 10-30%. This is due to technical limitation of common asphalt plant but also to specifications that are still restrictive when it comes to increasing RAP in surface courses. The mistrust in this practice is mainly related to uncertainty in performance of these mixes as well as to existing fundamental issues with the mix design, especially when production temperatures are lowered. This paper analyses some of the factors affecting the design of warm asphalt mixtures for surface course layers containing 50% RAP, and suggests a framework to justify the common assumption of full blending by optimising production conditions. A control hot mix asphalt which was manufactured with 49 dmm penetration binder and asphalt mixtures containing 50% RAP produced at temperatures between 95 and 135°C and at different mixing times were investigated in terms of volumetric properties, indirect tensile stiffness modulus, and indirect tensile strength. The highcontent RAP mixtures were produced within the warm mix region by using only a very soft binder as a rejuvenator, which reduces production costs. Statistical analysis was deployed, and different models were developed to estimate degree of blending between RAP binder and rejuvenator binder, and to predict the equivalent penetration of the blend without binder extraction and recovery. The analysis results showed that the selected performance indicators correlate significantly with mixing time and temperature, and provide evidence that only in certain circumstances and if the production conditions are accurately controlled, the practical full blending approach is acceptable.Keywords Reclaimed asphalt pavement (RAP) Á Degree of blending (DoB) Á Full blending Á Mix design Á Warm mix asphalt

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“…Rejuvenators, due to their rich maltene constituents and high permeation ability, can re-balance the composition of aged asphalt binders and have become the key material in pavement-recycling technology [1][2][3]. In recent years, many pavement materials have reached the end of their service life and have been abandoned in the city (Figure 1).…”

Section: Introductionmentioning

confidence: 99%

Micromechanism of the Dispersion Behavior of Polymer-Modified Rejuvenators in Aged Asphalt Material

2018

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Polymer-modified rejuvenator has a different composition and dispersion behavior to traditional rejuvenators. The objective of this study was to investigate the micromechanism of polymer-modified rejuvenators on the behavior of aged asphalt binder. Firstly, gel permeation chromatography (GPC) analysis was conducted to determine the dispersion effectiveness. Secondly, the dispersal behavior of polymer-modified rejuvenators was studied by means of atomic force microscopy (AFM) and scanning electron microscopy (SEM). Rheological, toughness-tenacity, and force–ductility analyses of the rejuvenated asphalt binder were additionally performed. The results indicate that the contacted asphaltenic micelles in aged asphalt binder were dispersed by dispersion agent in the polymer-modified rejuvenator, and that the dispersion ability of the polymer-modified rejuvenator was promoted to the commercial rejuvenator level. Additionally, the polymer-modified rejuvenator was found to improve the rejuvenated asphalt binder’s resistance to deformation, through the formation of polymeric network structures in the asphalt binder. The results may be used to improve the performance of rejuvenated asphalt binder in recycled-pavement engineering.

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Blending efficiency of Reclaimed Asphalt Pavement: An approach utilizing rheological properties and molecular weight distributions

Cited by 85 publications

References 12 publications

Thermal and Water Effects on Virgin Bitumen, Recycled and Mastic Mixtures

Thermal and Water Effects on Virgin Bitumen, Recycled and Mastic Mixtures

Design considerations of high RAP-content asphalt produced at reduced temperatures

Micromechanism of the Dispersion Behavior of Polymer-Modified Rejuvenators in Aged Asphalt Material

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