Determining the impact of degree of blending and quality of reclaimed asphalt pavement on predicted pavement performance using pavement ME design

Coffey, Sean; Dubois, Éric; Mehta, Yusuf; Nolan, Aaron; Purdy, Caitlin

doi:10.1016/j.conbuildmat.2013.06.012

Cited by 30 publications

(13 citation statements)

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“…When the RAP content is 40% and 50%, even with increasing the mixing temperature to 180°C, the DOB can only reach 87.5% and 80.5%, respectively, which is still that of a partial blending state. is conclusion is consistent with the research results of Coffey [18]. erefore, the current specifications for HMRAM design are not suitable to use.…”

Section: Pavement Performance Test Of Hmramsupporting

confidence: 89%

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

Chou

et al. 2019

Advances in Materials Science and Engineering

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In this study, the influence of the blending degree between virgin and aged binder on the pavement performance of hot-mix recycled asphalt mixture (HMRAM) with high RAP content is analyzed. The aggregate gradation of AC-16 was selected. The RAP contents were 30, 40, and 50%. HMRAMs with different degrees of blending (DOBs) were prepared by changing the mixing temperature (150, 165, and 180°C) without the occurrence of excessive aging for asphalt binders. An improved Hirsch dynamic modulus prediction model was then used to quantitatively characterize the DOB of HMRAM. Finally, the high-temperature, low-temperature, moisture stability, and fatigue resistance performance of HMRAM were tested and the effect of the DOB between the virgin and aged asphalt binder on the pavement performance was analyzed. The results showed that the DOB between the virgin and aged asphalt binder cannot reach 100% at the three mixing temperatures for HMRAM with 30, 40, and 50% RAP contents, which is inconsistent with the assumption of complete blending in China’s specification. The dynamic stability of the mixture gradually decreases with the increased DOB for HMRAM with a high RAP content, while the moisture stability, low-temperature, and fatigue resistance performance are continuously improved. This means that with the increase in DOB in the stage of open to traffic, meeting high-temperature performance criteria at the design stage may become unsatisfactory for HMRAM. The moisture stability, low-temperature performance, and fatigue resistance performances of HMRAM measured at the design stage were reasonable and conservative. The change in DOB significantly affects the content and properties of total free binder in HMRAM, affecting pavement performance. The content and physical properties of the RAP aggregate also have a significant impact on pavement performance.

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Section: Pavement Performance Test Of Hmramsupporting

confidence: 89%

“…Stephens et al [17] found that prolonging the preheating of the RAP resulted in a higher DOB, which increased the unconfined compressive strength and splitting strength of the recycled asphalt mixture. Coffey et al [18] measured the DOB of three kinds of HMRAM with an RAP content of 25%. All the DOBs obtained are higher than 85%.…”

Section: Introductionmentioning

confidence: 99%

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

Chou

et al. 2019

Advances in Materials Science and Engineering

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“…The amount of RA binder that is possibly activated during the manufacture of new asphalt mixtures containing RA has been described in the literature using various terms and definitions -the degree of blending (DOB), the degree of (re)activation, mobilised binder, mobilisation rate, blending efficiency, binder blending, etc. (Huang et al, 2005;Al-Qadi et al, 2009;Shirodkar et al, 2011Shirodkar et al, , 2013Navaro et al, 2012;Coffey et al, 2013;Bowers, Moore, et al, 2014). All these concepts are associated with two opposite scenarios related to the behaviour of the RA in this context, namely "full blending" (100% DOB) and "Black Rock" (0% DOB).…”

Section: Introductionmentioning

confidence: 99%

A practical approach to estimate the degree of binder activity of reclaimed asphalt materials

Pires

Presti

Airey

2019

Road Materials and Pavement Design

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A practical approach to estimate the degree of binder activity of reclaimed asphalt materials Using Reclaimed Asphalt (RA) in new asphalt mixtures can reduce the amount of new material required thereby saving money and natural resources. In addition, asphalt mixtures with RA have shown comparable properties and performance to that generally associated with asphalt mixtures made with 100% virgin material. However, RA content in pavement surface layers is still limited due to specification and technical limitations. For higher contents, the aged RA binder must be analysed to accurately determine the requirements for virgin binders and additives while the degree of blending (DOB) between the RA binder and the virgin binder also needs to be quantified. This is not a simple process and generally designers assume one of two opposing theories associated with 100% (full blending) or 0% ("Black Rock") DOB.This paper proposes a new approach to estimate a unique property of the RA known as the Degree of Binder Activity (DoA) as a function of the processing temperatures of the RA. The study showed positive results and indicated that this DoA approach can be used as a tool to better understand RA in order to improve the binder/blend design for recycled asphalt mixtures.

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“…However, the DoB can be affected by the production conditions for the same RAP incorporation level and properties, because increasing mixing temperatures reduces RAP binder viscosity which leads to higher RAP binder activation. Coffey et al [11] defined the DoB as the mobilisation percentage of RAP binder in an asphalt mix. They estimated the DoB based on air voids content by assuming the initial DoB is 70% based on literature, if this assumption was true then the air voids at 75 gyrations has to be 4%, if not then the binder content has to be adjusted based on a revised DoB percentage.…”

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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Determining the impact of degree of blending and quality of reclaimed asphalt pavement on predicted pavement performance using pavement ME design

Cited by 30 publications

References 1 publication

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

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

A practical approach to estimate the degree of binder activity of reclaimed asphalt materials

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

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