Particle clustering phenomena in hot asphalt mixtures with high content of reclaimed asphalt pavements

Bressi, Sara; Cavalli, Maria Chiara; Partl, Manfred N.; Tebaldi, Gabriele; Dumont, André-Gilles; Poulikakos, Lily D.

doi:10.1016/j.conbuildmat.2015.09.052

Cited by 63 publications

(32 citation statements)

References 7 publications

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“…A possible hypothesis is that a lower mixing temperature and less mixing time can lead to ineffective mixing between the neat bitumen and the RA mortar. Findings in literature support this hypothesis [36]. Another observation that strengthens this hypothesis is the presence of lower levels of carbonyls and the absence of high carbonate groups in Area 2 compared to area 3 (Figure 9a, Figure 10a, Figure 9b, and Figure 10b, correspondingly) which is an indication of a low degree of blending.…”

Section: Chemical Imagingsupporting

confidence: 53%

On the Applicability of ATR-FTIR Microscopy to Evaluate the Blending between Neat Bitumen and Bituminous Coating of Reclaimed Asphalt

et al. 2019

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The utilization of Reclaimed Asphalt (RA) in the road construction sector induces considerable economic and ecological benefits. The blending of the recycled material with new components is believed to be of great importance for the mixture’s properties. An extensive knowledge of the blending of the materials is crucial in optimizing the use of RA, especially at higher recycling rates. In this paper, the applicability of Fourier transform infrared (FTIR) microscopy in attenuated total reflectance (ATR) mode to study the bituminous coating of RA granulates is investigated. This method is a promising alternative to trace heterogeneous areas within the coating compared to methods that require extraction and recovery of bitumen. A method for sample preparation and FTIR spectra analysis is proposed. Four different samples were analyzed: a reference RA granulate, two types of RA granulates mixed with neat bitumen, and a RA granulate with rejuvenator. The results show that the use of ATR-FTIR microscope allows the tracing of different components, indications of blending, as well as proof of rejuvenation of the aged bituminous area.

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Section: Chemical Imagingsupporting

confidence: 53%

On the Applicability of ATR-FTIR Microscopy to Evaluate the Blending between Neat Bitumen and Bituminous Coating of Reclaimed Asphalt

et al. 2019

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“…The first is the phenomenon of particle clustering. Clustering can be defined as the agglomeration of RAP particles during mixing which leads to changing effective aggregate gradation and a decrease in the volume of free fine particles in the mix, thus affecting air voids content [29]. Increasing mixing temperature reduces RAP particle clustering by lowering RAP binder viscosity during mixing.…”

Section: Indirect Tensile Strength (Its)mentioning

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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“…Atualmente, em muitos países, são empregadas técnicas de reciclagem como forma de agregar valor à execução e à manutenção da vida útil dos pavimentos, visto que estas representam técnicas sustentáveis e alternativas economicamente viáveis. Portanto, visando a redução de custos e manutenção e, ainda, o aumento de sua vida útil aliado à questão ambiental, inúmeras tecnologias de reciclagem de pavimento estão sendo testadas e aplicadas por diversos autores [4][5][6][7][8][9].…”

Section: Introductionunclassified

Avaliação do comportamento de misturas asfálticas recicladas a quente com inserção de material fresado

Centofante

Specht²,

Almeida³

et al. 2018

Matéria (Rio J.)

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RESUMO Este trabalho tem por objetivo avaliar a técnica da reciclagem a quente em misturas asfálticas com relação às propriedades mecânicas, a fim de verificar a adequabilidade de seu emprego na substituição de material granular virgem por material reciclado do pavimento (fresado) em diferentes porcentagens, visando sua aplicação em camadas de pavimento. Para atingir este objetivo, foram realizados ensaios laboratoriais a fim de avaliar misturas contendo 10%, 20% e 30% de adição de fresado, comparadas a uma mistura de referência sem adição do agregado reciclado. Para avaliação de rigidez foram realizados ensaios de módulo de resiliência (MR) e módulo dinâmico uniaxial. Além destes, foram realizados ensaios de resistência à tração indireta (RT) e Flow Number (FN) para avaliação de resistência mecânica e, também, ensaios de dano por umidade induzida, através do Lottman Modificado, e desgaste no ensaio Cântabro, para avaliação das propriedades de adesividade e coesão das misturas, respectivamente. Através da análise dos resultados foi possível verificar uma importante economia do teor de ligante adicionado, visto que o material fresado contém ligante envelhecido e, assim, a redução de ligante novo variou de 12,9% até 35,7% para misturas com 10% e 30% de material reciclado, respectivamente. O experimento indicou que a adição de fresado em misturas asfálticas afeta o módulo e aumenta a rigidez das misturas; o ensaio de FN mostrou o ganho de resistência à deformação permanente das misturas, bem como não houve problemas significativos de desgaste e de adesividade, ou seja, as perdas encontradas são insignificantes e não comprometem a utilização deste material.

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Particle clustering phenomena in hot asphalt mixtures with high content of reclaimed asphalt pavements

Cited by 63 publications

References 7 publications

On the Applicability of ATR-FTIR Microscopy to Evaluate the Blending between Neat Bitumen and Bituminous Coating of Reclaimed Asphalt

On the Applicability of ATR-FTIR Microscopy to Evaluate the Blending between Neat Bitumen and Bituminous Coating of Reclaimed Asphalt

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

Avaliação do comportamento de misturas asfálticas recicladas a quente com inserção de material fresado

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