Reuse of Carbon Fiber Composite Materials in Porous Asphalt (PA)

Reuse of Carbon Fiber Composite Materials in Porous Asphalt (PA)

Figure 1: Porous Asphalt

What Is Permeable Pavement?

Permeable pavement is a great choice for storm water management; while it’s raining, it will reduce water runoff from the surface. A poorly designed runoff system leads to water pooling in some areas as well as flash flooding which can cause fatal accidents on highways.

Porous Asphalt (PA)

One type of permeable pavement is porous asphalt (PA). For low-volume pathways like parking lots, it is possible to use a porous asphalt (PA) mixture but for high-volume streets and roads, two layers of asphalt (1. Asphalt-treated permeable base, 2. Porous asphalt) need to be used.

Porosity and infiltration rates of PA have a direct connection to available air voids in PA. Higher air voids in PA means higher porosity and infiltration. On the other hand, higher air voids in PA means less strength and durability of the pavement.

Reuse of Carbon Fiber Composite Materials in Porous Asphalt (PA)

Figure 2: Comparison between Porous Asphalt and Conventional Asphalt [6]

Environmental Advantages of PA:

  • Restoring underground water
  • Increasing the quality of infiltrated water
  • Reduction in the usage of de-icing chemicals for winter maintenance of pavement
  • A detention basin is not required
  • Reducing demand on the sewer system
Reuse of Carbon Fiber Composite Materials in Porous Asphalt (PA)

Figure 3: Porous Asphalt [Google]

The performance of porous asphalt is highly affected by environmental conditions, such as thermal and ultraviolet oxidation and/or freeze–thaw cycles, which lead to surface raveling, moisture damage and durability concerns of using porous asphalt in cold regions. ¹ Through proper strengthening of PA, it is possible to increase the useful lifespan of the pavement by more than 20 years.

Adding fibers such as cellulose, polyester, polyethylene or cured carbon fiber composite materials (CCFCMs) to the PA mixture are suitable techniques of reinforcing PA.

Advantages of using CCFCMs in PA: ²

  • Minimizing drain-down and improving the uniformity of the PA mixture
  • Improving moisture resistance
  • Reduction of permanent deformation
  • Reduction of reflective cracking
  • Reduction of low-temperature cracking
  • Raising durability as a result of higher binder content

Facts About CCFCMs:

  • One type of fiber for a PA mixture’s reinforcement is reproduced from “Plate-Shaped Cured Carbon Fiber Composite Materials” (CCFCMs).
  • CCFCMs contain carbon fibers embedded in an epoxy matrix and are light-weight and high-strength. ³
  • CCFCMs amplify the physical and mechanical properties of PA.
  • CCFCMs are produced by shredding, milling and screening the plate-shaped CCFCMs and have three sizes of fibers, fine, medium, and large, and it has been shown that the size of CCFCMs affects the mechanical properties of PA.
Reuse of Carbon Fiber Composite Materials in Porous Asphalt (PA)

Figure 4: Various Sizes of CCFCMs [Google]

Advantages of CCFCMs for PA:

  • Drain-down prevention: The drain-down of asphalt to the bottom of the PA mixture during construction, storage or transportation of PA results in segregation of the asphalt in the mixture. Strengthening the PA mixture with fine CCFCMs can prevent the drain-down of asphalt.
  • Increasing indirect tensile strength: The IDT strength (indirect tensile strength) of PA reinforced with fine CCFCMs significantly increases by 33% and 21% at and  , respectively. ⁴
  • Rutting resistance improvement: The rutting resistance of CCFCMs-reinforced PA increases by about 22%. ⁴
  • High dosages of CCFCMs in PA mixtures reduce asphalt drain-down and voids closure so one can have a more homogenous mixture with a higher infiltration rate.
  • High dosages of CCFCMs improve ductility and cracking resistance of PA at low temperatures. It is recommended to reinforce a PA mixture for use in areas with low temperature.
  • High dosages of CCFCMs increase the strength of PA against freeze-thaw cycles.
  • The suggested dosage of CCFCMs in a PA mixture is 0.15% of the weight of the mixture. ⁵

Conclusion

“Carbon fiber” has a superb application in the “asphalt” industry. Through shredding, milling and screening of the “Plate-Shaped Cured Carbon Fiber Composite Materials,” it is possible to recover fibers for mixing into asphalt. For more information, kindly refer to the references of this article.

Authors

Parastoo Azad and Dr. Mehrtash Soltani (April 14, 2020)

References

  1. A. Lebens, B. T. (2012). Porous asphalt pavement performance in cold regions. Minnesota Department of Transportation.
  2. Kun Zhang, J. L. (2020). Field pilot study of porous asphalt pavement reinforced by cured carbon fibre composite materials (CCFCMs). International Journal of Pavement Engineering.
  3. Rodin, H. (2018). Enhancing mechanical properties of pervious concrete using carbon fiber composite reinforcement. Journal of Materials in Civil Engineering.
  4. Kun Zhanga, J. L. (2019). Reuse of carbon fiber composite materials in porous hot mix asphalt to enhance strength and durability. Case Studies in Construction Materials, 11.
  5. Kun Zhang, Y. L. (2021). Performance evaluation of porous asphalt mixture enhanced with high dosages of cured carbon fiber composite materials. Construction and Building Materials.
  6. Barnet, E. (2008). Porous Streets: the evidence.