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Performance of Porous Asphalt Mixtures Containing Recycled Concrete Aggregate and Fly Ash
Asad Elmagarhe1,2, Qing Lu1, Mohammad Alharthai3
1Department of Civil and Environmental Engineering, University of South Florida, Tampa, FL 33620, USA.
Materials (Basel, Switzerland)
|September 23, 2022
Summary
Recycled concrete aggregate (RCA) and fly ash can be used in porous asphalt, but may reduce performance. Adding fly ash as filler helps restore mechanical properties, making RCA a viable option for sustainable pavement.
Area of Science:
- Civil Engineering
- Materials Science
- Environmental Engineering
Background:
- Porous asphalt mixtures are crucial for effective pavement drainage and noise reduction.
- Construction and industrial waste materials offer potential for sustainable aggregate and filler replacement.
- Investigating the impact of recycled concrete aggregate (RCA) and fly ash on porous asphalt performance is key for sustainable infrastructure.
Purpose of the Study:
- To evaluate the effects of recycled concrete aggregate (RCA) and Type C fly ash on porous asphalt performance.
- To determine the optimal combination of RCA and fly ash for sustainable porous asphalt mixtures.
- To assess the influence of these waste materials on key pavement surface properties.
Main Methods:
- Laboratory preparation of porous asphalt mixtures with varying percentages of RCA (aggregate replacement) and fly ash (filler replacement).
- Testing of mixture performance parameters including air-void content, permeability, Marshall stability, indirect tensile strength, moisture susceptibility, Cantabro loss, macrotexture, and sound absorption.
- Comparative analysis of tested mixtures against a control mixture using granite aggregates and traditional filler.
Main Results:
- Incorporating RCA or fly ash slightly decreased air-void content, permeability, and macrotexture.
- A 10% RCA replacement reduced mixture stability, indirect tensile strength, raveling resistance, and sound absorption.
- Substituting mineral filler with fly ash compensated for the negative effects of RCA, restoring mechanical properties.
Conclusions:
- RCA and fly ash can be utilized in porous asphalt, but their impact on performance requires careful consideration.
- Fly ash acts as a beneficial filler, mitigating the adverse effects of RCA on mechanical properties.
- Optimized use of RCA and fly ash presents a sustainable approach to porous asphalt mixture design.
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