Evaluating and Modeling the Internal Diffusion Behaviors of Microencapsulated Rejuvenator in Aged Bitumen by FTIR-ATR Tests
Abstract
:1. Introduction
2. Experimental Method
2.1. Materials
2.2. Microcapsules Fabrication Processes
2.3. Preparation of Microcapsules/Bitumen Samples
2.4. Microcrack Generation
2.5. Morphologies Observation
2.6. FTIR-ATR Tests
3. FTIR-ATR Method and Theoretical Framework
4. Discussion and Results
4.1. Microcapsules/Bitumen Samples
4.2. Observation of the Microcrack Generation and Diffusion Behaviors
4.3. Microcapsules Contents Dependency of Diffusion
4.4. Mean Size and Shell Thickness Dependency of Diffusion
4.5. Aged Degree Dependency of Diffusion
4.6. Preliminary Model of Diffusion Coefficient
5. Conclusions
- The microstructure affected the D values of DPS in aged bitumen. A higher mean shell thickness decreased the D values because of the decrement of damage probability of microcapsules under the same content.
- With the same microcapsule sample in bitumen, the D values presented a trend of linear increase when the content of microcapsules was increased. All these results indicated that the microstructure greatly influent the diffusion behaviors based on the concentration of released rejuvenator.
- A preliminary model of diffusion behaviors of microencapsulated rejuvenator in bitumen was given based on the Arrhenius equation. This model considered the influence factors of microstructure, the amount of released rejuvenator and the age degree of bitumen. It is a guide to the construction and application of self-healing bitumen using microcapsules.
Acknowledgments
Author Contributions
Conflicts of Interest
Nomenclature
Diffusion coefficient | D (m2/s) |
Concentration | C (L/m3) |
Temperature | C (L/m3) |
Coordiante direction | x (m) |
Time | t (s) |
Diphenylsilane | DPS |
Microcapsule weight content | Wm (wt %) |
DPS weight content | WDPS (wt %) |
Microcapsules mean size | δsize (m) |
Microcapsules shell thickness | δthick (m) |
DPS weight content | WDPS (wt %) |
Core/shell material ratio | Rc/s |
Damage rate of microcapsules in bitumen | Dr (%) |
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Microcapsule Samples | Shell Thickness (μm) | Mean Size (μm) |
---|---|---|
M-1 | 1.2 ± 0.6 | 10 ± 0.45 |
M-2 | 2.6 ± 0.5 | 10 ± 0.40 |
M-3 | 1.5 ± 0.6 | 20 ± 1.53 |
M-4 | 2.7 ± 0.7 | 20 ± 1.53 |
M-5 | 1.6 ± 0.7 | 30 ± 3.52 |
M-6 | 2.7 ± 0.6 | 30 ± 3.08 |
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Su, J.; Wang, Y.; Yang, P.; Han, S.; Han, N.; Li, W. Evaluating and Modeling the Internal Diffusion Behaviors of Microencapsulated Rejuvenator in Aged Bitumen by FTIR-ATR Tests. Materials 2016, 9, 932. https://doi.org/10.3390/ma9110932
Su J, Wang Y, Yang P, Han S, Han N, Li W. Evaluating and Modeling the Internal Diffusion Behaviors of Microencapsulated Rejuvenator in Aged Bitumen by FTIR-ATR Tests. Materials. 2016; 9(11):932. https://doi.org/10.3390/ma9110932
Chicago/Turabian StyleSu, Junfeng, Yingyuan Wang, Peng Yang, Shan Han, Ningxu Han, and Wei Li. 2016. "Evaluating and Modeling the Internal Diffusion Behaviors of Microencapsulated Rejuvenator in Aged Bitumen by FTIR-ATR Tests" Materials 9, no. 11: 932. https://doi.org/10.3390/ma9110932