Comprehensive Assessment of Nano-Silica Modified Asphalt Mixtures: Influence of RAP Content, Aging, and Performance Characteristics
Using recycled asphalt pavement (RAP) in asphalt mixtures is common for improving sustainability, but it can lower performance because of the aging and hardening of RAP binder. Aged RAP is stiffer, less flexible, and more prone to cracking. The performance decreases with the age of RAP. Adding mater...
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Semnan University
2026-02-01
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| Series: | Journal of Rehabilitation in Civil Engineering |
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| Online Access: | https://civiljournal.semnan.ac.ir/article_9494_d41d8cd98f00b204e9800998ecf8427e.pdf |
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| author | Esmaiel Taheri Gholamali Shafabakhsh Mostafa Sadeghnejad |
| author_facet | Esmaiel Taheri Gholamali Shafabakhsh Mostafa Sadeghnejad |
| author_sort | Esmaiel Taheri |
| collection | DOAJ |
| description | Using recycled asphalt pavement (RAP) in asphalt mixtures is common for improving sustainability, but it can lower performance because of the aging and hardening of RAP binder. Aged RAP is stiffer, less flexible, and more prone to cracking. The performance decreases with the age of RAP. Adding materials like nano-materials can help reduce these issues. This study investigates the combined impact of RAP content, RAP age, and Nano-silica (SiO₂) on asphalt performance, focusing on fracture resistance, fatigue resistance, and moisture susceptibility. Asphalt mixtures with 25%, 50%, and 75% RAP were tested using two types of RAPs with different ages (5 and 10 years). Nano-SiO₂ was added in varying percentages (0%, 1%, 1.5%, and 2%) to evaluate its effects. The performance was assessed using the semi-circular bending test for fracture resistance, the indirect tensile fatigue test for fatigue resistance, and the tensile strength ratio (TSR) test for moisture susceptibility. Results showed that Nano-SiO₂ improved the fracture and fatigue resistance of mixtures, especially those with lower RAP content. At 25% RAP, the addition of 1.5% and 2% Nano-SiO₂ enhanced fracture and fatigue resistance by 15-20%. For mixtures with 50% and 75% RAP, Nano-SiO₂ led to significant improvements, with the best results seen at 2% nano-silica. Nano-SiO₂ also enhanced moisture resistance, increasing TSR values above the 80% threshold. Nano-silica mitigated the effects of aging, particularly in mixtures with higher RAP content. According to this comprehensive evaluation, it is recommended to use 25-50% of RAP using 1.5% of Nano-SiO₂ to achieve high-performance mixtures. |
| format | Article |
| id | doaj-art-bedbf1abee294f7fa3633252a421f14e |
| institution | OA Journals |
| issn | 2345-4415 2345-4423 |
| language | English |
| publishDate | 2026-02-01 |
| publisher | Semnan University |
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| series | Journal of Rehabilitation in Civil Engineering |
| spelling | doaj-art-bedbf1abee294f7fa3633252a421f14e2025-08-20T02:01:30ZengSemnan UniversityJournal of Rehabilitation in Civil Engineering2345-44152345-44232026-02-0114110.22075/jrce.2025.36705.22599494Comprehensive Assessment of Nano-Silica Modified Asphalt Mixtures: Influence of RAP Content, Aging, and Performance CharacteristicsEsmaiel Taheri0Gholamali Shafabakhsh1Mostafa Sadeghnejad2Ph.D. Candidate, Faculty of Civil Engineering, Semnan University, Semnan, IranProfessor, Faculty of Civil Engineering, Semnan University, Semnan, IranDepartment of Civil Engineering, University of Guilan, Rasht, IranUsing recycled asphalt pavement (RAP) in asphalt mixtures is common for improving sustainability, but it can lower performance because of the aging and hardening of RAP binder. Aged RAP is stiffer, less flexible, and more prone to cracking. The performance decreases with the age of RAP. Adding materials like nano-materials can help reduce these issues. This study investigates the combined impact of RAP content, RAP age, and Nano-silica (SiO₂) on asphalt performance, focusing on fracture resistance, fatigue resistance, and moisture susceptibility. Asphalt mixtures with 25%, 50%, and 75% RAP were tested using two types of RAPs with different ages (5 and 10 years). Nano-SiO₂ was added in varying percentages (0%, 1%, 1.5%, and 2%) to evaluate its effects. The performance was assessed using the semi-circular bending test for fracture resistance, the indirect tensile fatigue test for fatigue resistance, and the tensile strength ratio (TSR) test for moisture susceptibility. Results showed that Nano-SiO₂ improved the fracture and fatigue resistance of mixtures, especially those with lower RAP content. At 25% RAP, the addition of 1.5% and 2% Nano-SiO₂ enhanced fracture and fatigue resistance by 15-20%. For mixtures with 50% and 75% RAP, Nano-SiO₂ led to significant improvements, with the best results seen at 2% nano-silica. Nano-SiO₂ also enhanced moisture resistance, increasing TSR values above the 80% threshold. Nano-silica mitigated the effects of aging, particularly in mixtures with higher RAP content. According to this comprehensive evaluation, it is recommended to use 25-50% of RAP using 1.5% of Nano-SiO₂ to achieve high-performance mixtures.https://civiljournal.semnan.ac.ir/article_9494_d41d8cd98f00b204e9800998ecf8427e.pdfaging effectnano-silicafracture resistancefatigue lifemoisture susceptibility |
| spellingShingle | Esmaiel Taheri Gholamali Shafabakhsh Mostafa Sadeghnejad Comprehensive Assessment of Nano-Silica Modified Asphalt Mixtures: Influence of RAP Content, Aging, and Performance Characteristics Journal of Rehabilitation in Civil Engineering aging effect nano-silica fracture resistance fatigue life moisture susceptibility |
| title | Comprehensive Assessment of Nano-Silica Modified Asphalt Mixtures: Influence of RAP Content, Aging, and Performance Characteristics |
| title_full | Comprehensive Assessment of Nano-Silica Modified Asphalt Mixtures: Influence of RAP Content, Aging, and Performance Characteristics |
| title_fullStr | Comprehensive Assessment of Nano-Silica Modified Asphalt Mixtures: Influence of RAP Content, Aging, and Performance Characteristics |
| title_full_unstemmed | Comprehensive Assessment of Nano-Silica Modified Asphalt Mixtures: Influence of RAP Content, Aging, and Performance Characteristics |
| title_short | Comprehensive Assessment of Nano-Silica Modified Asphalt Mixtures: Influence of RAP Content, Aging, and Performance Characteristics |
| title_sort | comprehensive assessment of nano silica modified asphalt mixtures influence of rap content aging and performance characteristics |
| topic | aging effect nano-silica fracture resistance fatigue life moisture susceptibility |
| url | https://civiljournal.semnan.ac.ir/article_9494_d41d8cd98f00b204e9800998ecf8427e.pdf |
| work_keys_str_mv | AT esmaieltaheri comprehensiveassessmentofnanosilicamodifiedasphaltmixturesinfluenceofrapcontentagingandperformancecharacteristics AT gholamalishafabakhsh comprehensiveassessmentofnanosilicamodifiedasphaltmixturesinfluenceofrapcontentagingandperformancecharacteristics AT mostafasadeghnejad comprehensiveassessmentofnanosilicamodifiedasphaltmixturesinfluenceofrapcontentagingandperformancecharacteristics |