Investigation of the Effects of Aggregate Segregation on Asphalt Mixture Compactability

Abstract

The compactablility of asphalt mixtures refers to how easily these mixtures can be compacted to reach the target density. Proper compaction of asphalt mixtures is crucial for achieving the expected performance from the mixture. Aggregate segregation is defined as the concentration of coarse aggregates within the mixture in specific areas, and it is an important factor that affects the internal structure of the mixture. In this study, the effects of aggregate segregation on the volumetric properties and compactability of asphalt mixtures were investigated. To simulate different conditions, two groups of specimens were produced, applying the same compaction effort and targeting the same density. Unbiased-homogenous and segregated specimens at two levels were fabricated for each group using the Superpave gyratory compactor. To produce segregated samples, the mixtures prepared by combining the coarse and fine aggregates in the design gradation in different proportions and then placed in the mold in two layers before compaction. The volumetric properties of the produced samples were determined, and the compactability indices of the samples were calculated using the compaction curves. The results show that aggregate segregation significantly affects the volumetric properties and compactability of asphalt mixtures. It was also observed that the compactability of asphalt mixtures decreases with the increasing segregation level, and much more compaction effort is required to produce samples with the same target density.

Keywords

• Asphalt mixture
• Aggregate segregation
• Compactability
• Superpave
• Compaction energy index

Agrega Segregasyonunun Asfalt Karışımlarının Sıkıştırılabilirliğine Etkilerinin İncelenmesi

Abstract

Asfalt karışımlarının sıkıştırılabilirliği, karışımların hedef yoğunluğa sıkıştırılmasının ne ölçüde kolay olduğunu tanımlamak için kullanılmaktadır. Asfalt karışımlarının sorunsuz şekilde sıkıştırılması, karışımdan beklenen performansı elde etmek için çok kritiktir. Agrega segregasyonu karışımdaki kaba agregaların belirli alanlarda kümelenmesi olarak tanımlanmakta olup, karışımın içyapısını etkileyen önemli bir durumdur. Bu çalışmada, agrega segregasyonunun asfalt karışımlarının hacimsel özelliklerine ve sıkıştırılabilirliğine etkileri incelenmiştir. Farklı koşulları simüle etmek için aynı sıkıştırma eforu uygulanarak ve aynı hedef yoğunlukta olmak üzere iki grup numune hazırlanmıştır. Her grup için ön koşulsuz-homojen ve iki seviyede segregasyona uğramış asfalt karışımı numuneleri Superpave yoğurmalı pres kullanılarak üretilmiştir. Segregasyona uğramış numuneler üretmek için tasarım gradasyonundaki kaba ve ince agregalar farklı oranlarda birleştirilerek hazırlanan karışımlar kalıba iki tabaka olarak yerleştirilip sıkıştırılmıştır. Üretilen numunelerin hacimsel özellikleri belirlenmiş ve numunelerin sıkışma eğrileri kullanılarak sıkıştırılabilirlik indeksleri hesaplanmıştır. Sonuçlar, agrega segregasyonunun, asfalt karışımlarının hacimsel özelliklerini ve sıkıştırılabilirliğini önemli ölçüde etkilediğini göstermektedir. Artan segregasyon seviyesi ile asfalt karışımlarının sıkıştırılabilirliğinin düştüğü ve aynı hedef yoğunlukta numune üretebilmek için çok daha fazla sıkıştırma eforu harcanması gerektiği belirlenmiştir.

Keywords

• Asfalt karışımı
• Agrega segregasyonu
• Sıkıştırılabilirlik
• Superpave
• Sıkışma enerjisi indeksi

References

1. AASHTO R35. 2010. Standard practice for superpave volumetric design for asphalt mixtures, american association of state highway and transportation officials. AASHTO, Washington, DC, USA, pp: 154.
2. Azari H. 2005. Effect of aggregate inhomogeneity on mechanical properties of asphalt mixtures. PhD thesis, University of Maryland at College Park, Maryland, USA, pp: 1-441.
3. Bahia HU, Friemel TP, Peterson PA, Russell JS, Poehnelt B. 1998. Optimization of constructibility and resistance to traffic: a new design approach for HMA using the superpave compactor. J Assoc Asphalt Paving Technol, 67: 189-232.
4. Bessa IS, Branco VTFC, Soares JB, Neto JAN. 2015. Aggregate shape properties and their influence on the behavior of hot-mix asphalt. J Mater Civ Eng, 27 (7): 04014212.
5. Cai X, Wu K, Huang W. 2021. Study on the optimal compaction effort of asphalt mixture based on the distribution of contact points of coarse aggregates. Road Mater Pavement Des, 22 (7): 1594–1615.
6. Cross SA, Brown ER. 1993. Effect of segregation on performance of hot-mix asphalt. Transp Res Rec, 1417: 117-126.
7. Cross SA, Hainin MR, Ado-Osei A. 1998. Effects of segregation on mix properties of hot mix asphalt. K-TRAN: KU-96-6, Kansas, USA, pp: 1-117.
8. Chen MJ, Wong YD. 2017. Evaluation of the development of aggregate packing in porous asphalt mixture using discrete element method simulation. Road Mater Pavement Des, 18 (1): 64–85.

9. Debao L, Xiaoming H, Changlu G. 2013. Method to determine asphalt film thickness based on actual measurement. Adv Mater Res, 777-780, 140-143.
10. Dessouky S, Pothuganti A, Walubita LF, Rand D. 2013. Laboratory evaluation of the workability and compactability of asphaltic materials prior to road construction. J Mater Civ Eng, 25 (6): 810–818.
11. Dubois V, Roche CD La, Burban O. 2010. Influence of the compaction process on the air void homogeneity of asphalt mixtures samples. Constr Build Mater, 24 (6): 885–897.
12. Gao Y, Huang X, Yu W. 2014. The compaction characteristics of hot mixed asphalt mixtures. J Wuhan Univ Technol Mater Sci Ed, 29 (5): 956–959.
13. Georgiou P, Plati C. 2021. Microstructure characterisation of field and laboratory roller compacted asphalt mixtures. Road Mater Pavement Des, 22 (4): 942–953.
14. Guler M, Bahia HU, Bosscher PJ, Plesha ME. 2000. Device for measuring shear resistance of hot-mix asphalt in gyratory compactor. Transp Res Rec, 1723: 16–24.
15. Gong M, Xiong Z, Deng C, Peng G, Jiang L, Hong J. 2022. Investigation on the impacts of gradation type and compaction level on the pavement performance of semi-flexible pavement mixture. Constr Build Mater, 324: 126562.
16. Guo R, Zhou F, Nian T. 2022. Analysis of primary influencing factors and indices distribution law of rutting performance of asphalt mixtures. Case Stud Constr Mater, 16: e01053.
17. Hu T, Yuan J, Zhou X, Liu lu, Ran M. 2022. A two-dimensional entropy-based method for detecting the degree of segregation in asphalt mixture. Constr Build Mater, 347: 128450.
18. Huanan Y, Ming Y, Guoping Q, Jun C, Hongyu Z, Xiao F. 2021. Gradation segregation characteristic and its impact on performance of asphalt mixture. J Mater Civ Eng, 33 (3): 04020478.
19. Jiang J, Ni F, Gao L, Yao L. 2017. Effect of the contact structure characteristics on rutting performance in asphalt mixtures using 2D imaging analysis. Constr Build Mater, 136: 426–435.
20. Jin C, Jue L, Hengwu H, Junfeng Q, Miao Y. 2023. Numerical investigation of aggregate segregation of superpave gyratory compaction and its influence on mechanical properties of asphalt mixtures. J Mater Civ Eng, 35 (3): 04022453.
21. Jing H, Liu J, Wang Z, Chen H, Zhang X, Yuan L. 2023. X-ray computed tomography analysis of internal voids in steel slag asphalt mixture under freeze–thaw damage and microwave healing process. Constr Build Mater, 377: 131132.
22. Khedaywi TS, White TD. 1995. Development and analysis of laboratory techniques for simulating segregation. Transp Res Rec, 1492: 36-45, National Research Council, Washington, D.C.
23. Kwon O, Choubane B, Hernando D, Allick W. 2019. Evaluation of the ımpact of asphalt mix segregation on pavement performance. Transp Res Rec, 2673: 310-316.
24. Leiva F, West RC. 2008. Analysis of hot-mix asphalt lab compactability using lab compaction parameters and mix characteristics. Transp Res Rec, 2057: 89-98.
25. Liu H, Yin R, Wu S. 2007. Reducing the compaction segregation of hot mix asphalt. J Wuhan Univ Technol Mater Sci Ed, 22: 132–135.
26. Ma X, Leng Z, Wang L, Zhou P. 2020. Effect of reclaimed asphalt pavement heating temperature on the compactability of recycled hot mix asphalt. Materials, 13 (16): 3621.
27. Mahmoud AFF, Bahia H. 2004. Using the gyratory compactor to measure mechanical stability of asphalt mixtures. Wisconsin Highway Research Program 0092-01-02, Wisconsin-Madison, USA, pp: 1-85.
28. Mallick RB. 1999. Use of superpave gyratory compactor to characterize hot-mix asphalt. Transp Res Rec, 1681: 86–96.
29. Masad E, Jandhyala VK, Dasgupta N, Somadevan N, Shashidhar N. 2002. Characterization of air void distribution in asphalt mixes using x-ray computed tomography. J Mater Civ Eng, 14 (2): 122-129.
30. Masad E, Button J. 2004. Implications of experimental measurements and analyses of the internal structure of hot-mix asphalt. Transp Res Rec, 1891: 212–220.
31. Mohamed EHH, Abd El Halim AO, Kennepohl GJ. 1993. Assessment of the influence of compaction method on asphalt concrete resistance to moisture damage. Constr Build Mater, 7 (3): 149–156.
32. Onifade I, Jelagin D, Birgisson B, Kringos N. 2016. Towards asphalt mixture morphology evaluation with the virtual specimen approach. Road Mater Pavement Des, 17 (3): 579–999.
33. Rand DA. 1997. Comparative analysis of Superpave gyratory compactors and TxDOT gyratory compactors. Master Thesis, University of Texas at Austin, Texas, USA.
34. Roberts FL, Kandhal PS, Brown ER, Lee D-Y, Kennedy TW. 1996. Hot mix asphalt materials, mixture design and construction. Lanham, Md.: Napa Education Foundation, 2nd ed., Napa, USA, pp: 1-585.
35. Sefidmazgi NR, Tashman L, Bahia H. 2012. Internal structure characterization of asphalt mixtures for rutting performance using imaging analysis. Road Mater Pavement Des, 13 (sup1): 21–37.
36. Sefidmazgi NR, Teymourpour P, Bahia HU. 2013. Effect of particle mobility on aggregate structure formation in asphalt mixtures. Road Mater Pavement Des, 14 (sup2): 16–34.
37. Selvam M, NSSP K, Kandasami RK, Singh S. 2023. Assessing the effect of different compaction mechanisms on the internal structure of roller compacted concrete. Constr Build Mater, 365: 130072.
38. Shi J, Gong H, Cong L, Liang H, Ren M. 2023. Evaluating and quantifying segregation in asphalt pavement construction: A state-of-the-practice survey. Constr Build Mater, 383: 131205.
39. Stroup-Gardiner M, Brown ER. 2000. Segregation in hot-mix asphalt pavements, Transportation Research Board. Report no: 441, National Research Council, Washington, D.C., USA, pp: 1-95.
40. Taheri-Shakib J, Al-Mayah A. 2023. A review of microstructure characterization of asphalt mixtures using computed tomography imaging: Prospects for properties and phase determination. Constr Build Mater, 385: 131419.
41. Tashman L, Masad E, Peterson B, Saleh H. 2001. Internal structure analysis of asphalt mixes to improve the simulation of Superpave gyratory compaction to field conditions (with discussion). J Assoc Asphalt Paving Technol, 2001: 70.
42. Williams RC, Duncan Jr G, White TD. 1996. Hot-mix asphalt segregation: Measurement and effects. Transp Res Rec, 1543: 97-105.
43. Xuelian L, Siyu C, Kuiyuan X, Xueying L. 2018. Gradation segregation analysis of warm mix asphalt mixture. J Mater Civ Eng, 30 (4): 04018027.
44. Yu H, Zhou S, Qian G, Zhang C, Shi C, Yao D, Ge J. 2023. Evaluation of the microscale structure and performance of asphalt mixtures under different design methods. Constr Build Mater, 400: 132810.
45. Yücel AÖ. 2019. Investigation of the impact of aggregate segregation on rutting resistance of asphalt concrete. PhD thesis, Middle East Technical University, Graduate School of Natural and Applied Sciences, Ankara, Türkiye, pp: 1-212.
46. Zhang C, Wang H, You Z, Yang X. 2016. Compaction characteristics of asphalt mixture with different gradation type through Superpave Gyratory Compaction and X-Ray CT Scanning. Constr Build Mater, 129: 243–255.