Effect of RAP Dissociation and Agglomeration on Recycled Asphalt Binder Availability
Publication: Journal of Materials in Civil Engineering
Volume 36, Issue 9
Abstract
A milled recycled asphalt pavement (RAP) particle can be a cluster of one or more aggregates coated with an aged RAP binder. While RAP material is added to virgin aggregates and binder in a pugmill, the RAP cluster undergoes dissociation or agglomeration, depending on the cluster size and thermo-physical conditions inside the pugmill. The degree of dissociation or agglomeration of RAP material has an important relation with the degree of RAP binder availability. The RAP binder availability in mix design depends on the exposed surface area of dissociated coarse RAP particles and also on the agglomeration tendency of fine RAP particles. In the present study, the degree of RAP binder availability (DoAv), cluster dissociation of course RAP, and agglomeration tendency of fine RAP particles were examined at different mixing durations inside an asphalt pugmill—60 s, 120 s, and 180 s. The study examined whether the RAP cluster dissociation and postmixing agglomeration has any effect on the RAP binder availability. The degree of RAP binder availability of RAP mix was found by determining the virgin binder requirement of RAP mixes in excess of optimum binder content determined for the control mix prepared using virgin aggregates. Cluster dissociation and agglomeration was studied by hot mixing of RAP fractions in a pugmill with abrasive charges, followed by sieving. The statistical analysis of data found that RAP mixes incorporating fractionated fine RAP material exhibited higher DoAv at every mixing duration. For mixes incorporating fractionated coarse RAP, cluster dissociation index was positively correlated with DoAv, which implied that RAP cluster dissociation is a possible reason for RAP binder availability. In mixes incorporating fractionated fine RAP fractions, the RAP particles got agglomerated. The agglomeration index was found to correlate well with RAP binder availability, thereby establishing that agglomeration tendency in fine RAP fractions can be considered as an indicator of RAP binder availability.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
All data, models, and code generated or used during the study appear in the published article.
References
Bressi, S., M. C. Cavalli, M. N. Partl, G. Tebaldi, A. G. Dumont, and L. D. Poulikakos. 2015. “Particle clustering phenomena in hot asphalt mixtures with high content of reclaimed asphalt pavements.” Constr. Build. Mater. 100 (Dec): 207–217. https://doi.org/10.1016/j.conbuildmat.2015.09.052.
Gottumukkala, B., S. R. Kusam, V. Tandon, and A. R. Muppireddy. 2018. “Estimation of blending of rap binder in a recycled asphalt pavement mix.” J. Mater. Civ. Eng. 30 (8): 04018181. https://doi.org/10.1061/(ASCE)MT.1943-5533.0002403.
Kaseer, F., E. Arámbula-Mercado, and A. E. Martin. 2019. “A method to quantify reclaimed asphalt pavement binder availability (effective RAP binder) in recycled asphalt mixes.” Transp. Res. Rec. 2673 (1): 205–216. https://doi.org/10.1177/0361198118821366.
Lo Presti, D., K. Vasconcelos, M. Orešković, G. M. Pires, and S. Bressi. 2020. “On the degree of binder activity of reclaimed asphalt and degree of blending with recycling agents.” Road Mater. Pavement Des. 21 (8): 2071–2090. https://doi.org/10.1080/14680629.2019.1607537.
MoRTH (Ministry of Road Transport and Highways). 2013. Specifications for road and bridge works, 5th ed. New Delhi, India: MoRTH.
MS-2 (Manual Series). 2014. Asphalt mix design methods. 7th ed. Washington, DC: Asphalt Institute.
Pires, G. M., D. Lo Presti, and G. D. Airey. 2021. “A practical approach to estimate the degree of binder activity of reclaimed asphalt materials.” Road Mater. Pavement Des. 22 (5): 1093–1116. https://doi.org/10.1080/14680629.2019.1663244.
Raju, K. V. N. M., V. Radhakrishnan, and V. Chowdary. 2023. “Quantifying the degree of binder availability in recycled asphalt mix design using white and black rock mixes.” J. Mater. Civ. Eng. 35 (8): 04023237. https://doi.org/10.1061/JMCEE7.MTENG-15445.
Saliani, S. S., A. Carter, H. Baaj, and P. Tavassoti. 2019. “Characterization of asphalt mixtures produced with coarse and fine recycled asphalt particles.” Infrastructures 4 (4): 67. https://doi.org/10.3390/infrastructures4040067.
Stimilli, A., A. Virgili, and F. Canestrari. 2015. “New method to estimate the “re-activated” binder amount in recycled hot-mix asphalt.” Road Mater. Pavement Des. 16 (1): 442–459. https://doi.org/10.1080/14680629.2015.1029678.
Xu, G., T. Ma, Z. Fang, X. Huang, and W. Zhang. 2019. “The evaluation method of particle clustering phenomena in RAP.” Appl. Sci. 9 (3): 424. https://doi.org/10.3390/app9030424.
Yang, J., W. Tao, J. Gao, D. Yu, J. Zhou, L. He, and Y. Yao. 2021. “Measurement of particle agglomeration and aggregate breakdown of reclaimed asphalt pavement.” Constr. Build. Mater. 296 (Aug): 123681. https://doi.org/10.1016/j.conbuildmat.2021.123681.
Yang, X., J. Shen, and S. Kim. 2023. “Effect of clustering of reclaimed asphalt pavement particles on rutting performance of asphalt mixtures containing RAP.” J. Mater. Civ. Eng. 35 (8): 04023239. https://doi.org/10.1061/JMCEE7.MTENG-15364.
Zhao, S., B. Huang, X. Shu, and M. E. Woods. 2015. “Quantitative evaluation of blending and diffusion in high RAP and RAS mixtures.” Mater. Des. 89 (Jan): 1161–1170. https://doi.org/10.1016/j.matdes.2015.10.086.
Information & Authors
Information
Published In
Journal of Materials in Civil Engineering
Volume 36 • Issue 9 • September 2024
Copyright
© 2024 American Society of Civil Engineers.
History
Received: Aug 31, 2023
Accepted: Feb 9, 2024
Published online: Jun 19, 2024
Published in print: Sep 1, 2024
Discussion open until: Nov 19, 2024
ASCE Technical Topics:
- Aggregates
- Aging (material)
- Asphalt pavements
- Binders (material)
- Data analysis
- Deterioration
- Engineering fundamentals
- Engineering materials (by type)
- Infrastructure
- Materials characterization
- Materials engineering
- Methodology (by type)
- Particles
- Pavements
- Recycling
- Research methods (by type)
- Transportation engineering
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.