Mitigating RAP variability through detailed particle size classification: Applications in high RAP content asphalt mixtures

High recycled asphalt pavement (RAP) content in asphalt mixtures provides substantial economic and environmental benefits. However, its application is hindered by performance instability caused by RAP variability. This study investigates a refined RAP particle size classification method that increas...

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Main Authors: Guangji Xu, Zan Shen, Siwen Hao, Mengze Du, Jing Hu
Format: Article
Language:English
Published: Elsevier 2025-12-01
Series:Case Studies in Construction Materials
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Online Access:http://www.sciencedirect.com/science/article/pii/S2214509525007910
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author Guangji Xu
Zan Shen
Siwen Hao
Mengze Du
Jing Hu
author_facet Guangji Xu
Zan Shen
Siwen Hao
Mengze Du
Jing Hu
author_sort Guangji Xu
collection DOAJ
description High recycled asphalt pavement (RAP) content in asphalt mixtures provides substantial economic and environmental benefits. However, its application is hindered by performance instability caused by RAP variability. This study investigates a refined RAP particle size classification method that increases the grading levels from two to four, aiming to mitigate variability and enhance the performance of high RAP content mixtures. Laboratory-produced RAP was designed to simulate in-situ RAP properties with controlled variability in asphalt content, asphalt properties, and gradation. Recycled asphalt mixtures with RAP contents of 45 %, 60 %, and 100 % were evaluated for moisture sensitivity using immersion Marshall (retained stability) and freeze-thaw splitting tests (tensile strength ratio), low-temperature cracking resistance using semi-circular bending tests (fracture energy), and high-temperature stability using rutting tests (dynamic stability). Results demonstrate that RAP gradation variability predominantly impacts water stability, while asphalt content variability critically influences low-temperature performance. The refined classification method significantly reduced variability, enhanced mechanical properties, and stabilized overall performance. This approach offers a practical solution for improving the quality of high RAP content mixtures and advancing sustainable pavement construction practices.
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spelling doaj-art-bb08b08c22ae4a0786314871a48adc982025-08-20T03:31:30ZengElsevierCase Studies in Construction Materials2214-50952025-12-0123e0499310.1016/j.cscm.2025.e04993Mitigating RAP variability through detailed particle size classification: Applications in high RAP content asphalt mixturesGuangji Xu0Zan Shen1Siwen Hao2Mengze Du3Jing Hu4School of Transportation, Southeast University, Nanjing 211189, ChinaSchool of Transportation, Southeast University, Nanjing 211189, China; Nanjing Ziqi Transportation Industry Co., Ltd., Nanjing 211100, ChinaSchool of Transportation, Southeast University, Nanjing 211189, China; Corresponding author.School of Transportation, Southeast University, Nanjing 211189, China; Nanjing Modern Multimodal Transportation Laboratory, Nanjing 211100, ChinaSchool of Transportation, Southeast University, Nanjing 211189, ChinaHigh recycled asphalt pavement (RAP) content in asphalt mixtures provides substantial economic and environmental benefits. However, its application is hindered by performance instability caused by RAP variability. This study investigates a refined RAP particle size classification method that increases the grading levels from two to four, aiming to mitigate variability and enhance the performance of high RAP content mixtures. Laboratory-produced RAP was designed to simulate in-situ RAP properties with controlled variability in asphalt content, asphalt properties, and gradation. Recycled asphalt mixtures with RAP contents of 45 %, 60 %, and 100 % were evaluated for moisture sensitivity using immersion Marshall (retained stability) and freeze-thaw splitting tests (tensile strength ratio), low-temperature cracking resistance using semi-circular bending tests (fracture energy), and high-temperature stability using rutting tests (dynamic stability). Results demonstrate that RAP gradation variability predominantly impacts water stability, while asphalt content variability critically influences low-temperature performance. The refined classification method significantly reduced variability, enhanced mechanical properties, and stabilized overall performance. This approach offers a practical solution for improving the quality of high RAP content mixtures and advancing sustainable pavement construction practices.http://www.sciencedirect.com/science/article/pii/S2214509525007910Recycled asphalt pavementVariabilityParticle size subdivisionMechanical performanceCorrelation analysis
spellingShingle Guangji Xu
Zan Shen
Siwen Hao
Mengze Du
Jing Hu
Mitigating RAP variability through detailed particle size classification: Applications in high RAP content asphalt mixtures
Case Studies in Construction Materials
Recycled asphalt pavement
Variability
Particle size subdivision
Mechanical performance
Correlation analysis
title Mitigating RAP variability through detailed particle size classification: Applications in high RAP content asphalt mixtures
title_full Mitigating RAP variability through detailed particle size classification: Applications in high RAP content asphalt mixtures
title_fullStr Mitigating RAP variability through detailed particle size classification: Applications in high RAP content asphalt mixtures
title_full_unstemmed Mitigating RAP variability through detailed particle size classification: Applications in high RAP content asphalt mixtures
title_short Mitigating RAP variability through detailed particle size classification: Applications in high RAP content asphalt mixtures
title_sort mitigating rap variability through detailed particle size classification applications in high rap content asphalt mixtures
topic Recycled asphalt pavement
Variability
Particle size subdivision
Mechanical performance
Correlation analysis
url http://www.sciencedirect.com/science/article/pii/S2214509525007910
work_keys_str_mv AT guangjixu mitigatingrapvariabilitythroughdetailedparticlesizeclassificationapplicationsinhighrapcontentasphaltmixtures
AT zanshen mitigatingrapvariabilitythroughdetailedparticlesizeclassificationapplicationsinhighrapcontentasphaltmixtures
AT siwenhao mitigatingrapvariabilitythroughdetailedparticlesizeclassificationapplicationsinhighrapcontentasphaltmixtures
AT mengzedu mitigatingrapvariabilitythroughdetailedparticlesizeclassificationapplicationsinhighrapcontentasphaltmixtures
AT jinghu mitigatingrapvariabilitythroughdetailedparticlesizeclassificationapplicationsinhighrapcontentasphaltmixtures