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The Influence of Recycled Materials on Cold Mix with Foamed Bitumen Properties
Przemysław Buczyński1, Juraj Šrámek2, Grzegorz Mazurek1
1Department of Transportation Engineering, Faculty of Civil Engineering and Architecture, Kielce University of Technology, Al. Tysiąclecia Państwa Polskiego 7, 25-314 Kielce, Poland.
Materials (Basel, Switzerland)
|February 11, 2023
Summary
Recycled materials like reclaimed asphalt pavement (RAP) and recycled concrete (RC) enhance the stiffness of cold-recycled mixtures with foamed bitumen (FB). However, recycled aggregate (RA) showed no significant impact on dynamic modulus, and RAP quantity needs adjustment for optimal air void content.
Area of Science:
- Civil Engineering
- Materials Science
- Environmental Engineering
Background:
- Road construction generates substantial waste, necessitating sustainable practices through material recycling.
- Reclaimed asphalt pavement (RAP), reclaimed concrete (RC), and recycled aggregate (RA) are abundant byproducts of road demolition.
- Effective utilization of these recycled materials is crucial for environmental protection and resource conservation.
Purpose of the Study:
- To evaluate the impact of different types and quantities of recycled materials (RAP, RC, RA) on the properties of cold-recycled mixtures stabilized with foamed bitumen (FB) and Portland cement (CEM).
- To determine the optimal mix designs for incorporating recycled materials in road construction applications.
Main Methods:
- Laboratory testing of cold-recycled mixtures containing 20% to 80% recycled materials (RAP, RC, RA).
- Analysis of parameters including air void content, compressive strength, indirect tensile strength (ITS), water resistance (TSR), freeze-thaw resistance, and stiffness modulus (IT-CY, dynamic modulus).
- Consistent foamed bitumen (FB) and Portland cement (CEM) content across all tested mixtures.
Main Results:
- Both the type and proportion of recycled materials significantly influenced the properties of the FB-RCM mixtures.
- Mixtures incorporating reclaimed asphalt pavement (RAP) and recycled concrete (RC) exhibited high stiffness.
- Recycled aggregate (RA) did not yield noticeable changes in dynamic modulus under various loading conditions.
- Reduced reclaimed asphalt pavement (RAP) content is recommended to achieve desired air void content in FB-RCM.
Conclusions:
- Reclaimed asphalt pavement (RAP) and recycled concrete (RC) are effective in improving the stiffness of cold-recycled mixtures with foamed bitumen (FB).
- Recycled aggregate (RA) has a limited effect on the dynamic modulus of these mixtures.
- Careful consideration of reclaimed asphalt pavement (RAP) quantity is necessary to meet air void content requirements for optimal performance.
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