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

Abed, Ahmed; Thom, Nick; Presti, Davide Lo

doi:10.1617/s11527-018-1220-1

Cited by 40 publications

(10 citation statements)

References 9 publications

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“…Binder replacement ratios of 13.02%, 21.6%, and 38.37% were found for mixes with 15%, 25%, and 45% RAP contents, respectively. It should be noted that the mixing conditions were optimized as suggested by Abed et al [34] to maximize the degree of blending DOB between virgin and RAP binders so that the full blending assumption is reasonable. In this context, the mixing time was extended to 6 min for all mixes and the mixing temperature was maintained at 135 • C for warm asphaltic mixtures.…”

Section: Methodsmentioning

confidence: 99%

Effect of Chemical Warm Mix Additive on the Properties and Mechanical Performance of Recycled Asphalt Mixtures

et al. 2022

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Newer technologies such as warm mix asphalt (WMA) and reclaimed asphalt pavement (RAP) have gained international approval and have been considered as appropriate solutions that support the sustainability goals of the highway sector. However, both technologies present some shortcomings. The lower mixing and compaction temperatures of WMA reduce the binder aging and the bond between the aggregates and the coating binder, thus resulting in less rutting resistance and higher moisture susceptibility. On the other hand, RAP mixes tend to be stiffer and more brittle than conventional hot mix asphalt (HMA) due to the effect of aged binder. This tends to increase the crack propagation distresses. In an attempt to overcome their individual shortcomings, this study investigated the new concept of a combined WMA-RAP technology. The chemical WMA additive Rediset LQ1102CE was utilized with mixtures incorporating low (15%), medium (25%), and high (45%) RAP contents. Dynamic modulus (DM) and flow number (FN) tests were conducted to investigate the effect of Rediset on the behavior of RAP mixtures. The dynamic modulus |E*| mastercurves were developed using the sigmoidal model and Franken model was used to fit the accumulated permanent deformation curve. The results of this study showed that Rediset addition improved the cracking resistance of RAP mixtures. However, the rutting resistance was reduced but kept within the acceptable range except for mixtures containing low RAP content.

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Section: Methodsmentioning

confidence: 99%

Effect of Chemical Warm Mix Additive on the Properties and Mechanical Performance of Recycled Asphalt Mixtures

et al. 2022

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“…With a growing amount of milled RAP in developed countries, techniques and technologies that allow the highest possible percentage (up to 100%) of the RAP in the recycled asphalt mixture are developed [52]. Design considerations of high RAP-content asphalt produced at reduced temperatures were described by Abed et al [53]. However, the results of the study suggested that the full blending hypothesis is unpractical for the sake of asphalt plant productivity.…”

Section: Literature Reviewmentioning

confidence: 99%

The Correlation between the Number of Asphalt Mixing Plants and the Production of Asphalt Mixtures in European Countries and the Baltic States

2021

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The transport infrastructure’s pavement is made of asphalt layers, placed and compacted. The asphalt mixture is produced in an asphalt mixing plant (AMP) using expensive technological equipment which, when it becomes obsolete and worn out, is replaced with new equipment. One of the main problems related to the replacement process is that when it comes to purchasing new AMPs, the decision making involved is, in most cases, highly intuitive due to a lack of clearly defined criteria. In order to remedy this situation, this work presents an analysis of the correlation between the number of AMPs and the production of asphalt mixtures. Firstly, a correlation analysis was performed based on the European Asphalt Pavement Association (EAPA) data. Secondly, the current situation with the AMPs in European countries was analysed. Furthermore, a case study was performed and a system of nine criteria was created to identify why/when road construction companies operating in the Baltic States buy new AMPs. The weights of the criteria have been established by applying the Analytic Hierarchy Process (AHP) method. It was found that the most important criterion during the decision-making process for road construction companies is increased requirements for improving the quality of the asphalt mixture produced (criteria weight 25.0%). With a weight of 20.6%, the second vital criterion is the possibility of receiving support from European funds. The third criterion is the expectation of having a sizeable asphalt-paving site (weight 20.4%). The other six criteria are also significant, their weights varying between 1.6% and 13.5%. The industrial companies can use the obtained results for designing, producing and selling AMPs and adjusting strategic business plans.

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“…However, when pavement suffers severe distress and, as a result, no longer functions with satisfactory quality, pavement has to be reconstructed [ 1 ]. On the other hand, to address increased environmental concerns, an economic solution to deal with reclaimed asphalt pavement (RAP) is to reuse recycled materials in construction [ 2 ]. Specifically, a certain amount of RAP can be incorporated into the production of new asphalt mixtures, aiming to reduce resource consumption.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Mixing Conditions on the Macro-Scale Homogeneity of Asphalt Mixtures Blended with Reclaimed Asphalt Pavement (RAP)

Liu

Oeser

2021

Materials

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The homogeneity of asphalt mixtures blended with reclaimed asphalt pavement (RAP) is affected by many factors. Due to the complicated compositions of recycled asphalt mixtures, the inhomogeneity issue might cause insufficient mechanical properties of asphalt mixtures, even though a design method was appropriately adopted. Therefore, it is of great significance to study the influence of mixing conditions on the homogeneity of asphalt mixtures blended with RAP materials. This study focused on the macro-scale homogeneity of produced asphalt mixtures. Specifically, asphalt mixtures incorporated with 40% RAP content were produced in a laboratory using different mixing times and mixing temperatures. A multi-direction indirect tensile stiffness modulus (ITSM) test was proposed to quantify the homogeneity of produced samples. In addition, the digital image processing (DIP) method was used to identify the distribution of aggregates and RAP binder. The results indicated that the influence of mixing time on the macro-homogeneity of asphalt mixtures indicated that a longer mixing time was favorable for the material dispersion. The influence of mixing temperature mainly rested on two perspectives. One was that the temperature variation induced the change of binder viscosity. The other was that the temperature influences the diffusion process between RAP binder and new bitumen, which further affected the mechanical performance of produced asphalt mixtures.

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

Cited by 40 publications

References 9 publications

Effect of Chemical Warm Mix Additive on the Properties and Mechanical Performance of Recycled Asphalt Mixtures

Effect of Chemical Warm Mix Additive on the Properties and Mechanical Performance of Recycled Asphalt Mixtures

The Correlation between the Number of Asphalt Mixing Plants and the Production of Asphalt Mixtures in European Countries and the Baltic States

The Influence of Mixing Conditions on the Macro-Scale Homogeneity of Asphalt Mixtures Blended with Reclaimed Asphalt Pavement (RAP)

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